this is also a very good product that is self adisive
i use it not on aircraft but on a other application were a similar problem exists
http://solutions.3m.com/wps/portal/3M/en_US/3M-Automotive/Aftermarket/Our-Brands/VentureShield/
One needs something tough, because the fueller is going to throw a ~5kg metal item against the edge of the hole 
I will report on Version 3 at some stage But I know it won’t be practical because it will involve gluing the disk (the annulus) to the wing with epoxy, and since the wing is curved it will need to be weighed down until the stuff has gone off.
I had two more made without adhesive, and stuck them with epoxy. The result is good although really needs to be painted over
An update on this:
After some years, they start to crack. I think polycarbonate doesn’t take the UV, or the fuel. A different material is needed.
Couldn’t you just use an epoxy, coloured as needed? Like they use on garage floors or modern table tops.
The problem is that the filler hole edge is vulnerable, because it is a sharp edge. No way to protect it really. The proper way would be to machine up a “collar” which has a wrap-around inner edge so it goes a few mm down into the hole.
The “refuelling mat” method is a lot easier.
