Decided that I'd spend today looking at the only service job I'd never done since I bought the bike - checking and greasing the swingarm pivot and bearings. Got the 'pegs, clutch slave, chain cover, chain and rear wheel out, and thought everything was going really well until I tried to undo the nut holding in the chain-side cotter pin. The nut was just spinning round, on the partially stripped thread. With no room to get anything in underneath to split the nut off, I had to drill through the cotter pin from above using a right-angle drill, big enough (6.5mm) and deep enough (17mm) to break the stud portion off so that I could drift the large diameter portion out from underneath. The serious over-torquing of the cotters has deformed the pivot shaft so I need a new one of those, and the bearings had play so they'll need to be replaced also. Never straightforward, is it? I now have a unicycle, but at least being stuck at home means I have time to sort it properly!