Hi Richard,
My Sabre 04FD01 also started its service life with 14/20 hussars at wulfenbuttel in 1973, spooky that they're both in Dorset now. I'll dig out the rest of it's history to see if they have anything else in common,
I think you'll find that 2 A.D.S. stands for armoured delivery squadron.
All the best Andy