Hello Gordon,
I'm going to complicate matters and suggest you try three Morgans. To my mind the changes from an S1 to S4 Aero makes them totally different cars and worth driving both.
Servicing wise, and I do my own, the S1 is pretty easy, but can't comment on a Roadster. I did own a +8 before, but it was an early one pre-modern electronics, so a doddle for diy. A decent non-franchised garage that has a multi-make diagnostic computer should easily, imho, be able to do both a Roadster or an S1, and I presume therefore an S4.
Enjoy mulling over the matter, and more particularly good luck with whichever you buy.
Cheers
