Cossy
I think a whole weekend at a spa with close friends sounds brilliant. However if it was my wedding I would have a pre-planning “meeting” to ask my friends what they thought was reasonable in both cost and length of time, give them options and plenty of notice to save
I don't think it is all close friends though. It seems to be a mix of family, a couple of old schoolfriends, colleagues and a few random friends like my niece who will only know another former housemate, and slightly knows the bride's sister.
I imagine some of these weekends away can be very awkward - people who like lots of drinking versus people who are happy with a couple of glasses of wine, people who enjoy organised activities versus people who hate them, people who love clubbing and dancing versus people who would rather stick pins in their eyes.
And I do think the extroverts tend to dominate and make the quieter peop feel like wet blankets if they're not up for everything, downing lots of drinks, happy to dance until dawn etc.