Depends where you want to be. I use Pindale for big groups, Upperbooth has a barn and campsite.
Thornbridge is superb and would fit you in easily, Dark Peak have there family weekend there and there's 80+ go, but you need to book a year in advance.

If you are looking at a weekend in the not too distant future I think you will be very lucky to find that many beds, The rescue team are setting up a campsite for such a rthing but It won't be ready until next year if we get permission.