Nice site on MGBs:
Motor Gun Boats of WW2 - a particular story of a brave man
There used to be a few MTBs scattered about the South coast and in use as houseboats, certainly one in Hayling & one in Southampton that I remember were there for a long while.
Some examples:
British Power Boat Co.page 2 Save The Western Ladies - Other Fairmile Craft.
Looks like some serve on as tourist boats too:
Canadian Coastal Forces Kevin Wheatcroft recently bought this S-boot:
British Military Powerboat Trust.
Cheers,
Adam.