In Cathay cruise relief, second officers are not based in Europe. Maybe for two months if they get a temp base but the permanent home is Hong Kong for these guys. I know that FOs do the job of cruise relief but they are also FOs and get scheduled to do the FO bit also on flights. I think the original poster wanted to know about dedicated cruise relief such as SOs with Cathay who never operate as an FO. SOs do operate the freighters in CX but it is usually only due to roster disruptions of some sort and not the norm but does happen.