Unique in Britain or unique to Britain, as in you wouldn’t find anyone doing it anywhere else in the world?
The Beremeal mentioned above is the best example of that so far.
I think there’s only one company left in the UK making steam boilers.
Handmade bicycles doesn’t really count – all bicycles are handmade, they’re just not all handmade by white people.
Theres a whistle manufactures in Brum called Acme (yes really) that makes everything from policemans whistles to the whistles that sank on the titanic. Some friends of mine made the Acme Meteor with them, a 6ft impeller driven whistle designed to be dropped out of a plane from 10,000 ft, piloted by a skydiver and as it decends be the world’s loudest whistle
Back to Orkney and I think there was a guy making compact Cellos that were easier and cheaper for musicians to travel with
I worked with Blast Design last year, not unique in the fact that they work with explosives, but remarkable in the number of different ways in which they work with them.
Not really craft/artisan, but unique in britain rather than to Britain would perhaps be Air Salvage International, worked with them last year too. Bizzarely they’re based in the back corner of garden centre.
We’ve got a TV repairman down in the village, some of the TVs he works on are as old as television pretty much, and his shop window has a better collection than I’ve seen in many museums. His name is Baird too, appropriately.