Thanks for the kind words folks. Diesel can be so difficult to spot in the dry, easier in the wet. It was dry, but to be honest, I wasn't paying too much attention to the damp patch, because in my mind I was thinking it couldn't possibly be diesel as there was so much down. I'd sort of dismissed it as a wet patch, water or something. :(
Still, the bike's nearly fixed now (thanks to the boys at Phoenix), and at minimal cost. Having to fit the original pipe for now, until funds allow to get a fruity can again. To get myself back on the bike, I've had to get some kevlar jeans, because I can't get my swollen knee into leathers. Just hoping I haven't done any lasting damage to my knee (still bloody hurts)... >:(