Thanks for all the replies folk, it's nice to have people to talk it out with. I'm fine - right knee a bit bruised is all. Bike however less happy - cracked the mount for the front left fairing, and the gears felt funny, so got it recovered to the garage. Was hoping they'd ring today but guess I'll chase them Monday for the damage. They mentioned claiming on the insurance but I can't see that as economical - surely any money they pay me now I'm going to end up paying on higher insurance premiums for the next few years! I've thought about it and I think I was turning to the left, not sharply I don't think, but yeah, not completely neutral. Probably 10mph, down a steep hill, not braking just in a low gear. Then next thing I'm on my right side and a moment later I'm trying to yank my right foot out from under the bike as we sprawl in the middle of the lane. I felt nothing off the bike at all - other times I have felt the back slide and brought it back, this was nothing like that. Second-hand bike, I'm the fourth owner, previous two didn't do much on it but first owner put a good few miles down. Last owner had a pair of new tyres put on at the same time; his back tyre is the one I replaced. On reflection I shouldn't have filtered considered I knew there was diesel splash on the road, I was just on autopilot. We were all slow moving and tucked in together but I would have been safer staying in lane and leaving a bigger distance to spot the splashes. I didn't realise how dangerous it was as it was all over the road for previous half a mile and I must have crossed it multiple times (and I surely must have been giving some inputs there as well). Not quite sure why I didn't come off much earlier, I think that's part of why I'm so puzzled. Didn't know about the back tyre needing riding in to that extent - like I said, on my own and don't know any other riders, and garage didn't mention anything though they know I'm pretty new to this, so had no idea. We haven't done fifty miles together on that tyre yet so will be really careful when I get the bike back, thanks for mentioning it.