I only pay £330 pm for 3 small rooms within a department store. I am lucky cos it is all in so that is my only cost for my rooms. i don't have staff, it's only me. I have been in business here for a year now, prev working from home and I reckon that I am now slightly worse off than when I was working from home, even though my turnover has doubled. I do like going out to work, but I am far more stressed and I work much harder and my family see me less.
Would I do it again? I honestly don't know. If I had the spare room at home I think I would probably go back home now, because I have a lot more clients.
good luck and remember to negotiate everything. In this climate you could probably get a cheaper place to rent.