Yeah, mine is a mk2 F and has the later locks/ wiring that continued into the TFs. I'm not positive when they actually changed the lock wiring but probs around 2000.
I think it's just that many more of the later setups were produced, hence more being available on ebay.
If you check on Rimmers website it will tell you what chassis number they changed.
I had a similar sudden total lack of electrons that was fixed by disconnecting/reconnecting the battery with the isolator.
I took the isolator apart and found a small amount of corrosion/ build up on the brass was causing the issue. Cleaned it off and no further problems!