It depends on where you intend to do your flying. If in Europe, then I'd say do the revalidation, as the CAA/JAR license is valid in all JAR-registered a/c. Hence, all you'd need is the usual checkout and off you go.
If, OTH, you intend to do your flying in the US or other parts of the world (Africa, Oz), where a validation of your license is required anyway, then I'd say get the FAA ticket. Which, in any case, is valid in a G-reg also.