Shropshire, Northumberland, Forest of Bowland, Dorset all good suggestions. For what it’s worth, I quite like Barmouth and pretty much all of the Welsh coast. Criccieth or somewhere else on the Lleyn peninsula is another possibility.
I used to live in Shropshire where there’s Ironbridge Gorge, the Long Mynd and Ludlow. Authentic enough, rather than too touristy but with enough pubs and amenities.
And I grew up in Dorset. Perhaps somewhere like Seatown would appeal although some of the roads near Weymouth get busy. Portland, Durdle Door, West Bay all nice in their own way. Sherborne is nice but apart from the abbey, there’s not much to actually do.
Have a nice time, wherever you go.