With Class 1 rest facilities max duty with 3 pilots can be extended to 16 hours. None of the crew rest seats / facilities that I have personally seen in Global / Gulfstream aircraft have even complied with Class 3 rest facilities. That doesn’t mean they don’t exist of course, but I think a lot of EU operators are just dodging these regulations and using whatever seats / rest facilities (or even jumpseats!) they have without actually complying.
CP