G-ASYD, preserved at Brooklands, was the prototype (sort of) for the BAC 1-11 Type 475 and 670 Series.
The Bombardier CRJ 700/900/1000 Series prototype survives in CRJ1000 guise as S/N 19991 (was S/N 10001 originally, then 15991). The other CRJ700 prototype, S/N 10002, is now a Northrop Grumman test vehicle. Dash 8-400 prototype S/N 4001, is still flying as are Learjet 40/45 prototypes, 45-001 & 45-002. Canadair Challenger S/N 1002 is now a gate guardian at DND HQ while S/N 3991 is the ACT vehicle preserved at Rockcliffe, which also houses one of the CL-84 Dynavert aircraft.