The right hand side stand spotted at Old Warden was mine. I fitted it many years ago and seem to remember that it was a regular new old stock left hand stand. I removed the foot and had it welded back on in reverse. I may have had to jiggle other things around to make it work, but it certainly wasn’t difficult. Because it needs to be fitted behind the gearbox tray you do need enough length to hold the bike at a sensible angle, and I may have had to extend it slightly. The same left hand stands are still around at jumbles. I may even have a spare, but I’d need to find it.