The link you have found lists most of the recommended mods and upgrades which apply to pre 2014 cars, post 2014 cars have most of the upgrades from their initial build.
There is no advantage in buying a newer car car over an earlier car providing the major upgrades have been undertaken on the early car, with the exception of the Centa compensator they are easy to spot on the car. There are plenty of owners in the Berkshire area to give advice and of those two keep their cars outdoors. Take a look at Bell and Covills offerings as well, they also do servicing and maintenance.
You say you are only going to buy a car from a Morgan dealer, but this car
http://www.talkmorgan.com/ubbthreads.php/topics/602389/m3w-for-sale#Post602389 is well looked after with all the up grades in North London.
