Try increasing your salt intake as apparently most insects don't like salty stuff. Marmite is good and I know from experience that's Mrs Dukesox almost never gets bitten when we go away but the little phuquers love me. She eats tons of salt. Gin and tonic is supposed to be good for keeping them away too. Not sure if it is the gin or the tonic though. Lastly, lemons are good too but don't take your contact lenses out after squeezing a lemon even if you are Robert Plant, that really stings !