Audreys - the people mentioned below, who make Fortnums own brand chocolates - have
a virtual choc counter, where you can select what you want for a range of sized boxes.
Chococo are gorgeous. I do find most chocolate too sweet, and theirs isn't. It lets the chocolate taste come forward, but without the bitterness of some dark chocolate.
A Bristol company, Guilberts, do online orders. I don't think they are quite as good as the others I would recommend, but they're a lot cheaper, and a damn sight better than anything you could get from a supermarket. I rate them as better than Prestat Charbonnel etc, and head and shoulders above Hotel du Chocolat, and they're far less expensive than the first two, at least.
Rococo are wonderful but expensive. The owner apparently kickstarted the real chocolate trade in this country. I love their newer ranges - very creative. Speaking of which, Paul A Young is amazing, really unusual and considered flavours and wonderful quality. Again, so expensive, but actually for something special on the rare occasion, I think it's justified. They're unlike anything else. William Curley is fantastic as well. And if you want a brand nobody seems to have heard of, that's very quirky and British and delicious, Demarquette is great. Melt are impossibly stylish and also very delicious, but again, expensive. Artisan du Chocolat are also stylish and also imaginative and delicious, but I don't think, in fairness, that the quality is the same. But unless you're a lot richer than me, it does the job! (They also have amazing sales, especially just after Easter and Christmas which are well worth registering for. Plus a great basic box stuffed with lots of their chocolates for very cheap on Black Fridays, in the past - don't know if they will this year or not, given Covid.) If you want to go classic Belgian and have deep pockets, then you can't go wrong with Pierre Marcolini, either.
I don't really rate Prestat, Charbonnel or Hotel Chocolat. I think it's fairly sub-par chocolate with great branding. Very sweet and a lot of humectants etc.
Finally, Venchi make a Nutella original version which is just gorgeous beyond words. Nutella is full of horrible fats and pretty bad for you - Venchi's version isn't a health food, no, but it has a lot of nutrition in it despite the sugar. And it tastes about a hundred times better, too.
Yes, I have tried them all. I am just that greedy.