Rigidbody character cannot move once parented to platform

I searched my buns off looking for a solution but couldn't find any sorry for asking :(

My problem is that I have a rigidbody character and when I land on a moving platform I make the platform a parent of the character and the character moves with the moving platform which is the desired effect. However the movement controls no longer work once I'm on the platform, my character is effectively glued to the platform indefinitely. I have trouble shooted the bajeebas out of this and have had no luck, many thanks in advance for any light you're able to shed on this.

I have attached both my platform and character scripts

Here is the characterController script:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.SceneManagement;
 
 public class PlayerController : MonoBehaviour {
 
     public AudioSource coinAudioSource;
     public AudioSource goalAudioSource;
     public AudioSource jumpAudioSource;
 
     public float walkSpeed = 8f;
     public float jumpSpeed = 7f;
     public float turnSpeed = 2f;
 
     public bool isController2D = true;
 
     public bool pressedJump = false;
     public bool isJumping = false;
     public bool isGrounded = true;
     public bool isHeading = false;
 
     public HudManager hud;
 
     Rigidbody rb;
     Collider coll;
 
     // Use this for initialization
     void Start () {
         rb = GetComponent<Rigidbody> ();
         coll = GetComponent<Collider> ();
         hud.Refresh ();
     }
     
     // Update is called once per frame
     void Update () {
         //TurnHandler ();
         if (isController2D) {
             SideWalkHandler();
         } else {
             WalkHandler ();
         }
         JumpHandler ();
     }
 
     bool checkGrounded(){
         //get player collision dimensions
         float sizeX = coll.bounds.size.x;
         float sizeY = coll.bounds.size.y;
         float sizeZ = coll.bounds.size.z;
 
         //find the bottom points of the player
         Vector3 corner1 = transform.position + new Vector3(sizeX / 2, -sizeY / 2 + 0.01f, sizeZ / 2);
         Vector3 corner2 = transform.position + new Vector3 (-sizeX / 2, -sizeY / 2 + 0.01f, sizeZ / 2);
         Vector3 corner3 = transform.position + new Vector3 (sizeX / 2, -sizeY / 2 + 0.01f, -sizeZ / 2);
         Vector3 corner4 = transform.position + new Vector3 (-sizeX / 2, -sizeY / 2 + 0.01f, -sizeZ / 2);
 
         //cast rays from bottom four corners
         bool grounded1 = Physics.Raycast(corner1,new Vector3(0,-1,0),0.02f);
         bool grounded2 = Physics.Raycast(corner2,new Vector3(0,-1,0),0.02f);
         bool grounded3 = Physics.Raycast(corner3,new Vector3(0,-1,0),0.02f);
         bool grounded4 = Physics.Raycast(corner4,new Vector3(0,-1,0),0.02f);
 
         //Debug.Log ("Grounded: " + grounded1 + grounded2 + grounded3 + grounded4);
 
         return(grounded1||grounded2||grounded3||grounded4);
     }
 
     bool CheckHeadHit(){
         bool headed1 = false;
         float sizeX = coll.bounds.size.x;
         float sizeY = coll.bounds.size.y;
         Vector3 centerOfTop = transform.position + new Vector3 (0f, sizeY / 2 + 0.01f, 0f);
         Vector3 frontOfTop = transform.position + new Vector3 (sizeX / 2, 0f, 0f);
         Vector3 rearOfTop = transform.position + new Vector3 (-sizeX / 2, 0f, 0f);
         RaycastHit hit;
         if (Physics.Raycast (centerOfTop, new Vector3 (0, 1, 0), out hit, 0.02f)) {
             if (hit.collider.tag == "brick") {
                 hit.collider.SendMessage ("Hit");
                 headed1 = true;
             }
         }
         return(headed1);
     }
 
     void JumpHandler(){
         //get jump axis
         float jAxis = Input.GetAxis ("ButtonA");
         //Debug.Log ("jAxis: "+jAxis);
         isGrounded = checkGrounded ();
 
         //if jAxis exceeds 0f then make the player jump
         if (jAxis > 0f) {
             if(isGrounded && !pressedJump){
                 pressedJump = true;
                 //play jump sound
                 jumpAudioSource.Play();
                 //Jumping Vector
                 Vector3 jumpVector = new Vector3 (0f, jumpSpeed, 0f);
                 //Add jumping velocity
                 rb.velocity = rb.velocity + jumpVector;
             }
         } else {
             pressedJump = false;
             if (isGrounded) {
                 isJumping = false;
             } else {
                 isJumping = true;
                 isHeading = CheckHeadHit ();
             }
         }
     }
 
     void WalkHandler(){
         //set x and z velocities to 0
         rb.velocity = new Vector3 (0f, rb.velocity.y, 0f);
         //get distance
         float distance = walkSpeed * Time.deltaTime;
         Vector3 movement = new Vector3 (0f,0f,0f);
         //get inputs
         float hAxis = Input.GetAxis ("Horizontal");
         //get vertical axis input
         float vAxis = Input.GetAxis ("Vertical");
         //get movement vector 3D
         movement = new Vector3 (hAxis * distance, 0f, vAxis * distance);
         //get current position
         Vector3 currPosition = transform.position;
         //get new position to move to
         Vector3 newPosition = currPosition + movement;
         //move to new position
         rb.MovePosition (newPosition);
     }
 
     void SideWalkHandler(){
         //set x and z velocities to 0
         rb.velocity = new Vector3 (0f, rb.velocity.y, 0f);
         //get distance
         float distance = walkSpeed * Time.deltaTime;
         Vector3 movement = new Vector3 (0f,0f,0f);
         //get inputs
         float hAxis = Input.GetAxis ("Horizontal");
         //get vertical axis input
         float vAxis = Input.GetAxis ("Vertical");
         //get movement vector 2D
         movement = new Vector3 (hAxis * distance, 0f, 0f);
         //get current position
         Vector3 currPosition = transform.position;
         //get new position to move to
         Vector3 newPosition = currPosition + movement;
         //move to new position
         rb.MovePosition (newPosition);
     }
 
     void OnTriggerEnter(Collider collider){
         if (collider.tag == "coin") {
             print ("Grabbing coin...");
             coinAudioSource.Play ();
             GameManager.gminstance.IncreaseScore (1);
             print ("Score: " + GameManager.gminstance.score);
             hud.Refresh ();
             Destroy (collider.gameObject);
         }
         if (collider.tag == "goal") {
             print ("Reached goal!");
             goalAudioSource.Play ();
             Destroy (collider.gameObject);
             if (GameManager.gminstance.currentLevel == GameManager.gminstance.highestLevel) {
                 SceneManager.LoadScene ("you_finished");
             } else {
                 GameManager.gminstance.GoToNextLevel ();
             }
         }
         if (collider.tag == "enemy") {
             print ("Enemy hit, Game Over!");
             SceneManager.LoadScene ("game_over");
         }
     }
 }
 

Here is my platformController script:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlatformController : MonoBehaviour {
 
     Vector3 startPosition = new Vector3(0,0,0);
 
     public float moveDistance = 1f;
     public float moveSpeed = 1f;
     public float moveDirection = 1f;
 
     // Use this for initialization
     void Start () {
         startPosition = transform.position;
     }
 
     // Update is called once per frame
     void Update () {
         MoveX ();
     }
 
     void MoveX(){
         //how much are we moving?
         float movementX = moveDirection * moveSpeed * Time.deltaTime;
         //check the new position
         float newX = transform.position.x + movementX;
         //f the new position is too far change direction
         if (Mathf.Abs (newX - startPosition.x) > moveDistance) {
             moveDirection *= -1f;
         } else {
             //if we can move, move
             transform.Translate (new Vector3(movementX,0f,0f));
         }
     }
 
     void OnTriggerEnter(Collider coll){
         if(coll.tag == "player"){
             coll.transform.parent = gameObject.transform;
         }
     }
 
     void OnTriggerExit(Collider coll){
         coll.transform.parent = null;
     }
 }