On the taillights, the amber inserts are easy to remove and replace with just a pair of pliers and some coaxing
It's starting to make sense....I think... If I understand correctly,the rear lens I have already made is for the early model which much more of a 'lens' and is the version fitted to early and late model U.K spec cars.
Your photo is of the later model unit, where it appears that removing the amber shield is pretty straightforward without having to split the unit. Making this in clear would be pretty easy - I just wonder because it's just a cover rather than a lens, how beneficial it would be doing it in clear would be. I would guess that the improvement would not justify the price I would have to ask.
If as was suggested, this unit wasn't fitted to U.K cars, then I'll concentrate on the earlier model, which although more difficult, will benefit a lot more from the replacement, whether you fit an amber filament bulb or an LED cluster bulb.
Hope to have progress to report on the sides by middle of next week and also have cast the other side of the early rear with any luck.