Checking for collision after rotation

I'm trying to rotate an object, only if the rotated position is collision free. The object is made up of several child objects, each of which have their own collider.

The way I've gone about doing this is rotating the object, then checking if the object is in a collision. If it is, the object is rotated back to its original position. However, it seems my collision check is always returning true, so the block is always rotated back. Any ideas? I have a feeling that the children are colliding with each other, which makes the collision check always return true.

I'd also like to note that the collision check works in another part of my code, where I'm checking if a new position is collision-free (without rotation) but doesn't seem to work here.

Rotation

 // block rotation
 if (Input.GetKeyDown(KeyCode.Q))
 {
     this.transform.Rotate(Vector3(0, 0, 90));
     
     // if rotating puts piece in collision
     if (Collide(this.transform.position.x, this.transform.position.y))
     {
         // rotate back
         this.transform.Rotate(Vector3(0, 0, -90));
     }
 }
 else if (Input.GetKeyDown(KeyCode.E))
 {
     this.transform.Rotate(Vector3(0, 0, -90));
     
     // if rotating puts piece in collision
     if (Collide(this.transform.position.x, this.transform.position.y))
     {
         // rotate back    
         this.transform.Rotate(Vector3(0, 0, 90));
     }
 }

Collision Check

 // moves peice to specified position and check children for collisions
 function Collide(x:Number, y:Number)
 {
     // save position
     var oldX:Number = this.transform.position.x;
     var oldY:Number = this.transform.position.y;
     
     // move to new position
     this.transform.position.x = x;
     this.transform.position.y = y;
     
     // make sure none of children collide
     var count:int = this.transform.GetChildCount();
        for (var i:int = 0; i < count; i++)
        {
            var block:Block = this.transform.GetChild(i).GetComponent("Block") as Block;
            if (block.Collide(block.transform.position.x, block.transform.position.y))
            {
                // move back to original pos
                this.transform.position.x = oldX;
                this.transform.position.y = oldY;
            
                return true;
            }
        }
        
        // move back to original pos
        this.transform.position.x = oldX;
        this.transform.position.y = oldY;
        
        return false;
 }

Block Collision Check

 // checks for collisions at the specified position
 function Collide(x:Number, y:Number)
 {
     return Physics.CheckSphere(new Vector3(x, y, this.transform.position.z), 0.48);
 }