That sounds like a good idea Neil, thanks. I'll investigate on some self-leveling silicone. As you say, I do want to get the cover off again at some point. The seal only needs to be thin. Will try first on some bits not on the car.
I didn't want to paint the lens if possible - looking for some kind of very thinly based clear sealant which you can brush on, just to act as a barrier.
Has anyone had any experience of trying to make a water tight seal on the their front head light lens/covers, but without having to paint a black border under the lens or using foam underneath it? Looking for this effect:
I know this is a really old thread, but people still looking on how to work on their 608 mirrors. I've found a plastic credit card works better on popping out the mirror glass - doesn't damage any of the metal. Just pull back the lower edge of the mirror and slide the credit card in and work...