Since no one has replied, I'll try - but I'm a city girl - not really a landscape photographer!
The Lake District ('scuse my ignorance, but is this in Cumbria? if it's not, add Cumbria to the list - even though it's miles from London, it truly is STUNNING) The Peak District, the Dorset coastline, the Cotswolds. In Wales there are lots of opportunities, from the industrial wasteland of the valleys in South Wales, the Breacon Beacons in the middle and further north, Snowdonia. Once you are north of Swansea, the coastline in Wales is gorgeous.