One to add the research list if you're buying. We've recently had a lot of bed linen from Richard Haworth . Quality and service is fine, and their duvet covers are extra long with open ends so no fasteners to worry about, plus they have small openings in the top side corners to put your hands through to pull up the duvet while fitting them - which makes life a lot easier, and was the clincher for us.
They're a bit short on choice of material for fitted sheets.
We also ordered slippers; not as well made as the Out of Eden ones (which from personal experience seem to be indestructible!) but a better price and absolutely fine for use by guests for a week or two.
Might be worth a look - usual disclaimer, no connection other than as a customer.