I have one of those electronic fly swatters,shown in previous posts,I got mine from poundland last year and its great exercise,but I don't let the kids play with it though !
We have one of those battery operated fly swatters as well. One thing to be aware of with them, is NOT to trap a fly or whatever against the side of the tent when you zap it. The bats can emit a spark and, sorry if this offends anyone but we didn`t know this would happen, one fly literally burst into flames as it hadn`t fell off the bat before son zapped another. Luckily he had heeded my warning about not using the bat against the tent material, otherwise we could have had a hole in the tent
i use insect repellant. the type you would use on your self i dont spray it in the tent but onto a cloth then hang the cloth at the highest point in tent ( usually where the flies congregate trying to get out )
Lighter tent canvas and green canvas attract insects. Good old Vango blue doesn't! And for some reason, cotton canvas tents don't seem to get these bugs. So perhaps a dark (not green) cotton canvas tent is the answer?