I had to remove the vin plate on the windscreen pillar to remove surface rust and will put this back after paint.

I know there may differences in any laws between two countries affecting this type of thing. When i sand and prime the front trunk there are 2 plates in there that are riveted. These can be easily removed and replaced aswell as the above. Thete's nothing dodgy about the car (or me for that matter) and i'll refit them afterwards.

I'm not sure what to do about the sticker on the door jam though.

What's the best or done thing regards the sticker and new paint jobs?

It's staying the original L20e so no colour change contradicting the info on the sticker.

Don't know about the best way to do plates, but for vin stickers you can mask the sticker very carefully, press the tape down well, spread a little caulk along the tape edge to fill voids along the edge of the tape, and wipe off the excess. Then remove the masking after the color coat, and shoot clear over the whole works to help reduce the "step" around the sticker.

That's one way to do it. Look in the member vendor's section. There is a member here who makes new ones. That way it looks factory fresh. I carefully removed the old one, put on the new one. That way I still have the original sticker for the records.

The member who makes new door jamb stickers is socalandy. I bought one from him for my 914-6 a few years back. They're perfect.