There are lots of factors to consider here.
For example the price of property/rented accommodation in the southeast of England, especially London, is much more expensive than most of the rest of the UK.
The climate in southern England is much milder than the north of Scotland.
Although some areas of the UK are quite densely populated, most of it is rural. So, how rural do you want to be ?
Some areas are very isolated and quite rugged, some are good farming country and some are suburban.
Do you want to live near the mostly stunning coastline or further inland ?
Most places are very safe and the people welcoming.
I will suggest a few that you might want to research/Google further:
the Cotswolds (south of Birmingham)
the southwest (Cornwall, Devon, Dorset, Somerset and Wiltshire)
The Isle of Wight
Pembrokeshire (southwest Wales)
Cumbria (northwest England
East Anglia (Norfolk, Suffolk)
the Yorkshire Dales
Northumberland
southwest Scotland (Dumfries and Ayrshire)
There are many more in Wales, Scotland and Northern Ireland.
Most of the places in the brackets are counties not towns.
There are far too many candidates amongst towns and villages to list here but my choices, assuming money was no object, would be near Dorchester, Dorset or near St Ives Cornwall or near Taunton, Somerset.