Got a little more done today, some spring hangers for the front. You may notice that the spring is a touch oversized for the axle. I'm hoping someone here has had a go at shortening leaf springs before and can give some advice.
So far, I'm thinking cut it to length, weld it, then immediately immerse in some oil, then temper it (not in the kitchen oven?). I do have a spare in case it goes horribly wrong, and they weren't too expensive at £30ish each so I'm happy to experiment.
My other option as far as I see it, is to cut it, then drill a few holes in each side and bolt it back together with plates above and below tying it together (both sides on the same plane).
If anyone has any other thoughts and/or has tried either of these methods before, I'm very happy to take all advice available.