We are in winter..lol. oops just noticed a holy thread resurrection.I used the spray from screw fix (£10)...it did an excellent job. The foam is very accurate....it shoots about 4m so you don't need to get too close at all and it basically smothers the entire nest.
I did have a raiding party attempt an emergency takeoff as the ordnance was incoming on the nest but I was easily able to take them down without any bother at all with a bit of well directed anti aircraft fire.
As above...most will die off over the winter if you can wait a few months.