Hi Lizzie,
You need to consider costs for public liability insurance, employers insurance, building insurance, music licenses, licenses to hold clients personal details on site, there are a few more too...but they are the ones off the top of my head!
Also planning permission to the council if you are changing the use of your building, usually about £400, solicitors fees which usually work out at about £1500 (£250 an hour approx), accountants fees, which again to register this business with be between £300-£400 if you are going to be a Ltd company. Also deposits on your building, alot of landlords would like a personal guarantee and/or 3 months rent up front.
Need to think of costs for all equipment, furniture, products too.
BUT that said, once all that money is spent it will be very well worth it
Let me know if you have any more questions...
Charlotte x x