Hi, That pre 65 rule changed in 2012
In the 2011, the old rule book, said; "All 250 alloy beam(frame)up to Mk3" were OK for pre 65,
See 2014 rule 16.15.8.1,
"Acceptable for the pre65 class are machines and components built up to and including the 1964 model. The only exception to this rule if the model remains unaltered after this date".
must get the 2015 Manual of Motorcycle Sport,
yes unfortunately some people have been disappointed.
cheers