DM Longtown (Defence Munitions Longtown) is an Army depot not RAF or more correctly it's civillian

. It was run by the army(Royal Army Ordnance Corps and from 1993 Royal Logistics and then handed over to civilian control, probably as a money saving exercise. There was an RAF Carlisle but it is no more. There was also 14 MU (Maintenance Unit) (RAF stores), but that closed down as well.
When the Maid of the Seas was brought down over Lockerbie I was serving at 4 Ordnance Battalion HQ in Herford in Germany. I worked in the Combat Supplies office as a clerk. My job title on establishment was LCpl Combat

and my boss was an Ammo Tech Major. I didn't get to do much, just shuffling paper around. When my COs driver was busy elsewhere I was lemoned to act as Staff Car driver. No bad thing, he had a star plate on the front

. One morning I had to pick him up from his home and take him to work. At the appointed time I knocked on his front door to let him know I was there and returned to the car. The first thing he said when he got in the back seat was a 747 had crashed into Lockerbie. It was one of those "Where were you when " moments.
A few years later I worked for a parcel delivery company. One of the routes I had included CAD Longtown (Central Ammunition Depot, as it was then) and I got to enter some of the store sheds although not the one containing the plane, as far as I am aware. I had heard that the 747 had been recovered and transported to Longtown to be forensically rebuilt and stored. As far as I am aware it is still there. The whole Lockerbie thing is still an important event and every small addition to the story is reported on the Local News programme.