Kevr=
Mine is a j2, done about 8/9k miles and serviced regualry by previous owner.
Mine is booked in for this Thursday to get full complete service, oil change, filter, air filter, sparks, cambs.
I bought the parts myself from ebay as saved a bit as the garages like to mark up on parts and not always fit the best but more what is on offer to them.
My J2 is slightly noisy from the top end of engine, but im ensured by garage this is normal in a J2 needing a service and the above service would sort that no troubles.
I also bought a scot-oiler from ebay as well when buying the stuff, so after reading the instructions over and over ill prob end up challenging these guys to ensure i cut/modify the correct air/hydrolic line.