And a very picturesque one as well. I doubt they will have Avgas there, not many piston AC fly to DG, although there is a wrecked Catalina in the trees on the other side of the lagoon from the airfield. I have the info at work and will post it here when I find out in a few days. If there isn't, I wouldn't try to ship some out there. The Royal Marine det often have to wait op to one year for some supplies they demand!
Although it is a US Mil base, the British Governer has the say so on all events on the Island. It is through the 'Brit Rep' as he is known that you will have to put your request. E mail me for contact numbers.