Currently film4 is SD and therefore will be decrypted by the HDR-FOX T2 when exporting to an external drive via USB.
There is a small possibility that this process corrupted the file on export.
Have you tried more than 1 file?
Are you sure you are attempting to play the ts file and not one of the side car files which have different file extensions?
Have you tried the ts file on a more traditional operating system to check they are OK? Try an alternative player like MPC-HC (Media Player Classic Home Cinema), or even VLC.
What on your MS Surface 2 are you using to play the file? It could be that it does not support the ts file’s codecs. The default player has a poor reputation for the breadth of what it can play.
A version of VLC is expected very shortly to be available from the app store. It will be free and will not rely on the RT 8.1 codecs. Avoid anything which describes itself as VLC and charges as it will be a fake.