British-owned Chocolate?
Classic question. The ones that are bought out by large (usually American) foreign companies almost always get worse over time.
Bad examples: Cadbury - Mondelez Hotel Chocolate - Mars
Good examples (afaik): Montezuma Booja-Booja Gnaw
Any others?
Whitakers - recently bought by Bramble Food Group from Leicester. However, a Whitaker is still in charge and their factory remains in Yorkshire.
Demarquette Fine Chocolates - still family run in London.
Cwtsh Chocolate - still run by its founder in South Wales.
If we are in the spirit of buying European, then Thornton's is at least Italian.
Divine is good. Based in London and manufactured in England, but roughly half owned by a cocoa farmer's cooperative in Ghana.
Monty Bojangles - London based, British Owners
Mrs Tilly's - Larbert based, Scottish Family Owners
Mackies - Aberdeenshire based, Scottish Family Owners
Buchanan’s Confectionery - Greenock based, owned by Golden Casket
I’ve bought Kernow Chocolate for a few Christmas gifts before - it’s really good: https://www.kernowchocolate.co.uk/
Audrey's Chocolates - based in Brighton