I don't know about in Devon, and a lot would depend on at what price things could be produced, but up here in Cumbria there are always one-man bands (usually farmers moonlighting, of course) making bespoke or small-run trailers and other items for farmers and smallholders.
We had an all-terrain tipping large round hay bale quad trailer made, for less than half what the commercial ones cost, and with a much cleverer wheel setup.
And I'd been inspired to look into that, having used a farmer-made tipping silage quad trailer on the previous farm.
You can't get Quadlocs any more.
We just had ours adjusted to take a new, wider quad bike. If someone made something similar - or that met the same need - we and many other farmers would be in the market. Ditto ways of locking other items up more safely.
There's a company up here makes a cleverly-designed small sheep trailer, undercuts Ifor Williams and has better panel and gate arrangements, and the braked version comes in under the weight that younger drivers can tow without a special license.
We'd buy a water carrier trailer for the quad. Especially if it would be adaptable for towing behind quad, car or tractor.
And so on.