The list is short on purpose
Places worth a bed.
Not a gazetteer. Eleven bases you can actually stay in, with the night count written down so the week does not dissolve into day trips.
Country
Mood
Getting there

England
London, as a hinge
Two nights, then leave
London is the airport, the railhead, and a good dinner. It is a poor place to spend a short British holiday if you also want a coastline.
2–3 nights · No car

England
Bath and a quieter west
A walkable stone city
Bath is compact, on the railway, and easy to overstay once you have done the centre. Pair it with one day that is not the famous crescent.
2–3 nights · No car

England
The Cotswolds, edited
One village, not eight
The honey stone is real. So are the coach parks. Stay in one village with a pub and a footpath, and refuse the village-hopping circuit.
2–3 nights · Car helps

England
The Cornwall coast
Harbour first, beaches second
Cornwall pays you back in weather and seafood if you stay put. July and August rent the coast to everyone else. Shoulder months are the product.
3–4 nights · Car helps

England
The Lake District
Boots, not a scenic drive
The Lakes are a walking region that tolerates cars and punishes people who treat them as a driving tour. Pick a valley and stay in it.
3–4 nights · Car optional

England
York and a day on the rails
A walled city that still works
York is the rare small city that is both famous and useful: walkable, on the main line, and a base for one countryside day without a car.
2–3 nights · No car

Scotland
Edinburgh
The city that earns three nights
Edinburgh is the British city most worth a proper stay: walkable, theatrical in bad weather, and a clean rail start for the Highlands.
3–4 nights · No car

Scotland
A Highland road
One glen, not the NC500
The Highlands are a weather system with a road through them. The loop-the-whole-north itinerary is how hire cars and tempers get wrecked.
3–4 nights · Car helps

Scotland
Glasgow
The city Scotland actually lives in
Glasgow is warmer in mood than its weather, cheaper than Edinburgh, and a better food city than its reputation south of the border allows.
2–3 nights · No car

Wales
Eryri
Mountains with a railway
Eryri — still called Snowdonia on half the road signs — is the mountain trip you can start by train. Yr Wyddfa is optional. The valleys are not.
3–3 nights · Car optional

Wales
The Pembrokeshire coast
A path, a tide, a town
Pembrokeshire is the coast path people mean when they say Wales surprised them. It is also a long way from London. Give it the nights.
3–4 nights · Car helps