Hi guys,
I've managed to fix it.
Do a full factory reset, all settings, and then also do an 'Initialise personal information'. It then asks 'Are you sure' and talks about it deleting all kinds of things, including 'last played, connection information etc'. I suspect that some setting Iplayer doesn't like is stuck in a cache somewhere which is cleared on the initialisation of personal info.
The player then restarts. I ran through Easy setup for convenience then checked the menu. All apps for Music/Photo/Video had disappeared. Which is good, that's what I wanted. I updated internet information which repopulated everything. From this I assume that apps were actually re-installed, not just added to. Hopefully meaning I've got fresh clear copies now too. Rather like PC problems where only solutions are re-installing programs!
All working fine now! Hoping it fixes the Lovefilm streaming buffering issues I've been getting recently too.
Rather conveniently Lovefilm has remembered my player so I don't need to relink it either.
Thanks to Sony reps for their help. I hope this answer helps other customers having the same or similar problems.
