manchester sauna scene... whats the etiquette for couples turning up vs single guys

right so weve been hearing manchester has this whole sauna scene thats different from the proper clubs and im a bit confused on how it works... is it mixed couples and singles all the time or are there couples only sessions?? the missus is up for it but shes worried itll just be a sea of single blokes and we'll feel cornered. anyone whos actually been to the manc saunas recently can u tell us what to expect on a tuesday or weds night... also do u just rock up or is there a booking thing nowadays