Hi Dave
My A65P banged horribly when the forks were at full extension.
The first problem found was that the expert classic car restorer had fitted short springs.
Back in the day, I had a good supply of springs from the factory. BSA made a range of grades & also supplied Triumph springs. The Triumph springs were graded between the BSA rates and were slightly stiffer than the equivalent BSA items, thereby doubling the options available.
As nobody seemed to know this, I had a set of springs wound by a Sheffield company and cut down a nylon bush, from a local bearing supplier, to length to give a very slight preload - the total cost was no more than buying springs of unknown origin. The preload prevented the clanging. Achieving the same effect would have been possible, if I had specified longer springs, but the factory had put me onto using spacers.
I never found much, if any, real benefit from Eddie Dow's dampers & even he said they were a step towards pretending a sow's ear was a silk purse.
The later Triumph shuttle forks are much better, but so far I haven't found anyone making & supplying new sliders. (working on a length of thick wall ally tube shouldn't be too big a task)