Mattressman for beds (I phone the trade side for extra discount). They normally deliver next day.) AO is also good at next day delivery, will consolidate orders (John Lewis, who get manufacturers to deliver white goods, don’t) and also supply small electricals.
Robert Dyas for basics (though mainly a Southern chain) as it is then easy to replace their white China. Or very large supermarkets. Asda is cheapest.
Really worth finding a Homesense for linen, and a few classy touches. (Fruit bowl, serving dishes, lamps, cushions, rugs etc) It’s the homes part of TKMaxx (and is wonderful).
You need to be able to cook and serve a roast dinner. And people have all sorts of expectations. Egg cups!
Don’t forget pictures on walls. Colour is needed. Think about a DVD player for kids and rainy days, or set up Netflix.
I always leave cleaning stuff and plenty of washing and dishwasher tabs. They don’t cost much and are appreciated. And cafetière coffee and decent tea.
Towel racks - lots! Otherwise heavy damp beach towels get hung on radiators or bathroom towel rails.
And order the WiFi early, and get a good speed. Bored kids stream a lot.
I got an antiques dealer friend to buy a flat full of furniture from auction. Some very chic Italian sofas and some nice G Plan stuff. For bedroom furniture I often go to Oak Furniture land as they will deliver within a couple of days.