Off to mallorca a week on friday for a stag(plus 3 extra days, just to chill) got the flights for £50 just last week, which is amusing as most paid much more than that months ago!
skyscanner bingo suggests:
from Birmingham you can get to Paris for £80 a head. No idea what that would be like for a stag, you can also get to Faro for £108 but the Sunday flight back is brutal.
from Bristol you can get to
Geneva for £80
Basel for £96
Pisa for £108
Again, no idea of the suitability of these destinations for your group, I’ll let you check suitability for flight times.
Anyhow, it’s simple. just got to skyscanner, your airport, your dates and everywhere for destination, and up will pop your options.