Rentokill do 2 wasp killersFoam and powder.
I have used the powder which we got from Wilkinsons but you can get
both on line
I puffed the powder into the nest entrance at night and the nest was
dead by the next evening,
I have also used a similar product when I had wasps comming into a
glasshouse after grapes, I put the powder down on the 4 points of
entry I found and the carried it back to theire nest/s, I put powder
down over 3 days and after that no more wasps.

I used to have a bad allergy to wasps till I underwent a desenticising
course which lasted around 30 weeks,

Wasps are busy at this time of year building their nests and expanding
the colonies. towards the end of Aug onwards they become more of a
problem as their numbers reack their peak and as the weather cools
they get more agressive.

On the pluss side they do feed on a lot of garden pests such as
aphids, catapillars etc at this time of year.

David Hill
Abacus Nurseries