Melvyn Rutter purchased a load of old Plus 4 stuff from the Factory some time ago. He still has considerable stocks. Otherwise Gee for chassis, Billy Bellinger for moss box stuff etc etc, see ads in Miscellany.
1969 4/4 1995 plus 8 1996 Plus 4 4seater 2002 Aero S1 2013 M3W 2014 Plus 8