When I sold my ten year old Plus Four via Revolutions with eight years non Morgan servicing ie using local garages, it made no difference to what they paid me and they sold it immediately for a good price.
Not sure about other main dealers - maybe with only one dealer in Scotland they have to be practical on servicing options.
I did have the Aero serviced at Ledgerwood and will continue main dealer servicing for the Plus six.
Distance is a pain but manageable with one car rather than two.
You know it makes sense! 
