This sounds very much like what happened to me yesterday. I was clearing up in the border, having sprayed insect repellent (with neem oil) on my arms and legs. Despite that (and despite avoiding the pond area, bebcause I am a mozzie magnet) I was bitten three times — on each ankle, on my midriff and on my face — by what appeared to be small, darkish-coloured bug-like insects, which drew blood. They were definitely not mosquitos or horseflies. I got the impression they bit when disturbed by my removing their home to be composted.

The bites are extremely painful, despite hydrocortisone cream, antihistamine tablets, ice and co-codamol. I too would very much like to know what infliected them

If I am to finish what I started, I will need to wear more clothing and stronger insect repellent, and will probably spray some insecticide on that part of the border a couple of hours beforehand.