Hi,
I don't want too sound obvious, but you need to catch/kill one and present it to the exterminator guy. As you are probably aware, wild ( large) Bees are not aggressive unless really provoked, honey bees are small and usually totally ignore humans, whereas, wasps are nasty little things ( some really big ones about) and will really not take "no" for an answer. Bees will not sting, as they will die, wasps take great pleasure in stinging. The wasp season is nearly over, usually August, then the September rain comes and they all go into their nest for the winter, dreaming up new ways of annoying humans, so with any luck, as soon as this hot spell ends ( depends where you are, but most people had a really hot day today) they will be gone, but it may be worth talking to you neighbours, as the wasps appear to be nesting in hedges now. I have found two wasps nests in two years, one was in a cardboard box in my garage, the other, a beautiful, large. hanging thing like a christmas lantern, in my loft. luckily, empty. an absolute work of art, cannot beleive that a small thing could build a nest a foot long and 10" wide.
so they could be nesting anywhere.
good luck.
annie.