Gosh, Steve - sorry to hear of your airborn troubles. Sounds vile. The worst I've ever been bitten was a few fly/gnat type bites on the Suffolk coast (Dunwich, to be precise), many years ago. That was mainly at night, but we got a plug-in repellent which helped a lot.

I've also heard that some people are more attractive to flying insects than others - and that lemon juice or lemon scented stuff is effective as a preventive - but that's perhaps just hearsay.