Wasps nest in loft - getting in up'n'under eaves

Have you played with petrol amd matches? Not really recomended petrol is far too volatile, the vapours build up quickly and go with quite whomph when ignited. BTDTGTTS when I was a lad, campfire "assisted" by about tablespoon of petrol visibly leapt 6" into the air...

Paraffin is far safer and you don't even need to set fire to it, it kills pretty quickly on contact.

wee follow up - discovered some old ant killer, which contains bendiocarb (the active ingredient in wasps nest removers I noticed). So on Saturday night, when all was quiet, I managed to shake some into the top of the bottle, and puff a good amount into the gap twice. Sunday morning found 4 dead wasps on the step. Since then I haven't seen any wasps at all. So a result I guess.

I'll seal up the eaves now ... the reason there was a gap was a screw holding the security light bracket in place had pulled the T&G wood down too much. It needs a spacer.

So thanks to all for the advice.