Right. The definitive answer: we picked sloes and bullaces. The berries all looked the same to me, so I googled the leaves, which are totally different. Not a damson in sight, and no bums either
They've all been pricked and drowned in gin now. I was so inspired, I made a bottle of blackberry vodka at the same time. Unfortuntely not all the vodka would go back in the bottle, so I've had to drink it as it might go off. Hic.