Jaz - just getting hold of a set of the UK-spec Rear Lights is akin to finding Rocking Horse Dung these days.
A decent set go for about £250-300, if and when you can find them. And then you need the Trim pieces as illustrated above, and a little welding, and a bit more re-wiring, and....you'd be better off sticking to what you've got already !
I managed with wikipedia to translate and understand THAT bit - it was the bit you left off that confused me................"if and when you can find an ignorant seller and steal 'em off for £300 !"
put it this was I asked him to do my wedding photo's... it was like we took a double take and thought the pictures were of a different car.. he took the right angles to avoid the dents and scrapes and rust holes.
we over paid for the car tbh but... it's given us the opportunity to work on a car to bring it to the way we wanted it.