Brilliant, cheers SO, I didn't think to look it up on Wiki, my usual first port of call.Not a drop short, but the 3.7 AA gun is also an option.
ETA: from Wiki:
For the British Army, it fulfilled a role between field artillery tractors (FATs) such as the Morris C8 Quad, which towed smaller guns such as the 25-pounder gun-howitzer, and the Scammell Pioneer, used for towing the 7.2-inch howitzer. It was commonly used to tow the 5.5-inch medium gun and the QF 3.7-inch AA gun. The Matador was found to be a generally useful vehicle and was adapted for other roles, including carrying a 25-pounder gun. (I'm assuming this last phrase refers to a portee.)
AEC Matador - Wikipedia