I've been a few times to City Sauna and it's always felt rushed to me. Thirty minutes seems to mean you get the *room* for 30 minutes, not the girl, so you get shown to the room to prepare, then she takes her time to swan in around 5-10 minutes into the 30, then she wants you to finish early so that she doesn't have to pay the place extra for your "extra" use of the room - that last bit is actually what one of the girls told me once. There are better places in Sheffield with better girls at better prices - by the time you've counted in all the deductions, £45 for "30" minutes actually means £45 for about 15 minutes which is £180/hour pro-rata, which for the relatively low quality shags you get at that place is severely overpriced. Maybe they pulled a fast one on me or something, but hey, newsflash, pulling fast ones leads to unhappy and therefore ex-customers. It's my experience at Sauna that makes me always check the time the girl enters the room, wherever I go.
At other places I've been a 30 minute booking means you get the *girl* for 30 minutes and prep before plus cleanup afterwards might mean you actually have the room for 40-45 minutes or so. I'd rather go to Honeypot or Unit 8.