Dead Easy
No 1 AIDU RAF Northolt will sell to civilians the RAF plates in their unclassified catalogue at a very reasonable cost as they do ERCs, FLIPs etc etc.
They also do very cheaply excellent spiral bound books of all the plates for various regions at only slightly inferior print quality to single specific sheets. I used to love those brown booklets.
Very good value all their products although rather too prevalent ERC typos are irritating but not serious (eg OYSTER for OYSTR).
So get on that web, contact civilian sales. But hey, I thought Leuchars and Lyneham were the UK emergency 24hr diversion airports, Brize is closed for resurfacing and Fairford is only of interest to 99, 216, the civvy contractor all of whom get RAF plates anyway?
There is also the DIGITALAERO DAFIF site promulgated by US DoD. Easy to search for. But anything the RAF and USAF provide is an indulgence, not a right.