3300John:
in many books it tells you MJ2711 is the first ERF.
MJ2711 (chassis 63) was rebuilt in the 1970’s using at least two donor C.I. ERF’s wasn’t it John?. I have all the photos somewhere - including the donors used, one other of which I think was chassis 88. In one photo they had managed to snap in half the original “E.R. Foden & Son Diesel” radiator badge!.