Accessing binary files non-sequentially in c# on Android

I'm building a game that will have multiple large (multi MB) binary data files that I don't want to load into RAM all at once.

Here is an example of what I have that works on windows but not on my target device which is Android.

 byte[] bytes = new byte[1000];
 FileStream fs = new FileStream (Application.dataPath + "/MyData", FileMode.Open, FileAccess.Read , FileShare.Read);      
 fs.Seek (2177, SeekOrigin.Begin);
 fs.Read (bytes, 0, 1000);

I need an equivalent method that will work on Android.

I've looked at Resources.Load() & BinaryReader() but they don't seem to give me an option to read a specific part of the file, and my searches have not found anything useful.

Any help would be appreciated.

P.S. Even though I'm new to unity I don't think I've overlooked anything that should be obvious, but if I have I'm sure you will let me know :).