Regarding the difference between Mk1 and Mk3-4 waffle box pipes.
The different design of the heads means that the exhaust outlets are closer to the frame in the Mk1, therefore pipes are almost straight where the later models require a fair bend so that they enter the woffle box at the correct angle.
Terry, if you do not already have straight pipes to "tweak" I suggest it would be cheaper to get the correct bends made up, there are numerous exhaust pipe benders that will do the job, regarding TT tubes that Eddie mentioned, the last time we approached them they were not too keen, rather surprisingly, as they had always been so helpful in the past, its interesting that you found the same. If you want details of anyone that will do one offs let me know via email and I can dig you out the details. One snag with my usual company is they really like to have the bike on site so they are confident they have them right!!