I have replaced all four corners on my Greyhound. The front ones because they were odd and then the back ones because one started to leak and did not do a lot. The front complete with springs were made by Leda who offer adjustable dampers or not. They went bust, but their successors again Leda took over the manufacture and made me a pair for the back. They are at: 20, Victoria Road, Draycott, Derby. Phone: 01332 871821. I think they have a web site so try a search. They list the Greyhound and Cobra on their product list. Regarding your grooved washers, they are standard Triumph TR4A (the bottom trunnion is angled and handed) or above, so if you go to Moss, Rimmer Bros or James Caddock they have the parts lists on line so you can see what it is you want. A service kit for both sides is not very expensive but they now use through bolts rather than the splined pin that was originally used and fitted to AC's, so you do not have to split the wishbone. I think Koni(Ikon) make coil overs too. If you do a search for suspension units as I did originally, I had a feast of a time looking at suspension bras for athletically fit women playing tennis in their bras!