I don't know how, I don't know why, but it's working again. I took the battery to a mechanic yesterday and he charged it and tested it when I went back today to reveal that there's nothing wrong with the battery... i'm not sure this is good news... if it's not the battery, it's probably something more serious... Most likely it's loose wiring or it's the starter motor, either way it's not great. I put the battery back in, turned the key... nothing.
OK. Either way a push start should get it going, I will just have to park on hills for the next little while. Round up some boys to push start it and put Andy in the drivers seat as he's torn his calf and won't be heaps of use for pushing the car and then just as we're about to start pushing Andy turns the key and brrrrrr-brrrrrrrrr-BRRRRRRRRMMMMMM!! The engine kicks to life after 2 days of not eliciting so much as a struggling groan, unbelievable. I'm still parking it on hills just in case but it has been starting fine since.