Thank you @TiredOfCleaning. We've had such an awful time and I've recently been diagnosed with cancer so I've been panicking about how I'm going to manage looking after us both while I have treatment. The back payment will help with some of that and once I'm on a more even keel I know exactly what private therapy I'll be getting on board. I'm still in utter shock. I thought I was going to have to appeal but had already resigned myself to the fact that I likely won't have the energy for that soon, so I'd all but written it off.
Good luck to everyone else. I hope that by sharing my timeline it might at least help someone. I've lurked in the background and I know it's been helpful for me to get an idea of timescales.