Today I removed my rear wheel arch liners and dug out 16 years worth of built-up crud from behind them, slapped on some Hammerite where it looked like it was needed and reassembled. Also noticed my fuel filler pipe was covered in rust, so I sanded and painted that (as much of it as you can do while it's in situ, I figured that was better than nothing - that is the bit that's exposed after all). I was going to do the front arches as well but the heat got the better of me (roasting hot on the south coast at the moment), so that can wait till another day. I did treat a couple of spots of surface corrosion on the front subframe and anti-roll bar though.
And now, of course, my hands and forearms are covered in splodges of black Hammerite which won't come off! Swarfega didn't seem to do much, any suggestions?