The council may do it for you - give them a call and speak to their pest control centre.
If not, they should die in the winter anyway, so in January, you can get rid of the nest if there is one, and find and seal the places where they are getting in.
Cost us about £40.00 from the wasp man at the council to remove one from our compost bin.
Be careful - my husband got badly stung getting too near and we ended up in A&E.
Interestingly wasps never use the same nest twice so if you ever find an empty one in your house you may as well leave it - we've got one in our loft- it's been there for years.
Just don't go into the loft until it gets colder as the wasps will then be dead. Then you can remove the nest and admire it for the work of art it is. Been there, done that and would never have dreamt of paying a "wasp man" to remove it.
if the wasps have conducted themselves without attracting attention until now, it's unlikely they'll bother you much now that the season is almost at an end. in a few weeks the problem will sort itself.....
Great comments from the good folk here...... Personally though, I would be wondering how they got in the loft in the first place, so would either wait till they die in the colder weather or pay the £40 or so pounds for them, and the nest, to be taken out and obtain report as to where they coming in from....pay for firm to seal up if reasonable or do it myself if quoted something silly, otherwise you are going to have the exact same problem in the Spring.
Answerprancer.
Thank you for that fascinating link.
Must say though never heard bike used in that sense despite having spent the first 22 years of my life in Ayrshire.