For info, whilst up in Cumbria last week, I found the following frequencies being transmitted from the Great Dun Fell NATS site on the hills to the east of Penrith.
There is a tarmaced road up there, so you can walk /cycle if you feeling energetic! You can see the white radar dome from the M6 on a clear day.
125.475 London Information North (often bandboxed with London Info West & London Info East) (offset +7.5kHz)
126.6 London Volmet North (offset -5kHz) (It's also transmitted from Chedburgh in Suffolk)
No other civil ATC popped up.
282.125 Swanwick Mil NW ICF
277.775 Swanwick Mil NE ICF
251.25 Swanwick Mil "North" area (i.e Scotland) ICF
371.875 Swanwick Mil "North" area (i.e. Scotland)
No VHF freqs for Swanwick Mil that I could find.
I suspect there are other secondary UHF freqs for the NW and NE areas, but none popped up.
277.625 is not transmitted from GDF (It is from Kelsall)