I have a requirement to apply a clear finish over a model yacht moulding in pre-preg.

In short, the moulding is in 1k carbon cloth, and the surface finish is not perfect by some margin. The strength, quality, and accuracy of the moulding is fine.... but the aesthetic finish is poorer than it should be.

The mouldings are exposed to sunlight from time to time, not on a daily basis, maybe a couple of days a week at the best. Some will be in hot countries with intense sunlight though.
They will not be exposed to significant scratching, unless rough handling or accident occurs. They will be placed in water for short periods, sea and river/lake (model yachts!).

So what I am looking for is a clear finish that can be flatted and buffed up to an excellent finish, that has some degree of UV stabilisation, is temporarily saline resistant, has a degree of scratch-resistance(although not essential) and forms a good bond with the pre-preg(assuming it's properly keyed).

My thoughts turn to a quality automotive 2k polyurethane clear coat.

But has anyone any experience of this? Or are there other alternatives?