Reserve roles exist in specific reserve squadrons, which in turn are located at specific RAF bases. As you will not be resident at those bases (except on multi-day operations or exercises), geographic proximity to where you live is important. These are the bases where this role is active:
501 Sqn, RAF Brize Norton, Oxfordshire
502 Sqn, JHFS Aldergrove, Co Antrim
504 Sqn, RAF Wittering, Cambridgeshire
505 Sqn, RAF St Mawgan, Newquay
602 Sqn, Glasgow, Scotland
605 Sqn, RAF Cosford, Shropshire
606 Sqn, RAF Benson, Oxon
607 Sqn, RAF Leeming, North Yorkshire
611 Sqn, RAF Woodvale, Merseyside
Covesea Flight, RAF Lossiemouth, Moray