[squodgy]

Hopefully she'll give up & find the nearest alternative site which for the sake of your fears we can only hope is far away.....But it just may not be.
These things are fearsome by reputation, but a review of the books, sites and blogs seems to indicate they just want to be left alone to mind their own business and are NOT normally aggressive towards humans unless provoked.
If she is successful in establishing a nest the normal population isn't anything like our wasp, being in the low tens rather than hundreds.
As a deterrent I would spray the nest site with RAID Wasp Nest Destroyer from good hardware shops. I had to use it on a bee colony which lodged in our roof, because Council cutbacks under this lot of baboons meant no more pest help, the alternative was to cough up to 'professionals'.
Anyway, I sprayed as far in as I could and it wiped most out, with returning workers falling like flies feet from the entrance. Unfortunately the Queen was still alive & the colony re-grouped requiring another more sustained attack....which worked.