We've thought long and hard about this one, having been let down by a succession of different contractors who always say they'll get back to us but then disappear! The problem is that most spreaders either need a PTO, or are far too small for this kind of thing.
In the end, we've decided to use granulated lime (calcifert) instead. This comes in 600kg big bags, which I can collect locally using our 4x4 and trailer.
Then, the plan will be for Mrs Womble to drive us slowly round the fields, whilst my friend and I stand on the trailer, scooping the lime out and scattering it by hand as we go. Yes, I'd have loved to buy or make a spreader, but I have a hunch that this will work just fine, and will probably take less time overall than having to get the welder out.
I just need to get our Landy back on (or off!) the road, and we'll be ready to give it a try. I'll report back in due course, but if anybody has any tips in the meantime, I'd be glad to hear them!