Nick, it's really an honour to speak with a TT hero! According to what I know the TT course had many road improvements for the 1977 edition. It was the year of the suppression of the Snugborough corner at Union Mills, isn't it? So it's probable that the Ballaspur jump was flattened after the 1976 TT and before the 1977 TT.

It would be really an interesting thing to write a _detailed_ history of the changes of the TT course during the years. I think that in the last 30 years the two greatest changes happened on the TT course have been that for the 1977 TT and that for the 1985 TT (the remaking of the Quarry bends section). I saw on the 1974 Knight's book a photo of the first part of the Quarry section and it's really hard to recognize it! There was a lot of trees and adverse camber on the roads - now it's a permanent circuit TT coourse section!

Other interesting thing. Both in the 1974 and 1989 books, Ray mentions the Glen Auldyn jump as "now almost flattened". So I deduce that it must have been flattened after the 1962 (first TT course experience of Ray) and before the 1973.