wow I cant believe you didnt know this.
With regards to licenses it all depends on what treatments you do and if the local council requires it. All you have to do is call your local council and ask them and they will tell you what you need, unfortunetly it varys area to area!
With regards to PAT testing everyone using electrical equipment for the purpose of work needs to have the equipment tested every 12 months. Computers, Wax pots, Lights, HiFis etc all need this certificate. In general expect to pay between £50 and £200.
Look it up in the Yellow Pages under electricians. It shouldnt take them more than a couple of hours and they then stick a sticker on any equipment that passes or condemn any faulty items. The only time an item wont pass is if the thermostat on say heaters break and could cause fires or burning or electric shocks on you, any one you employ or clients.
If a client is injured from an item of electrical equipment I have known insurance companies not pay out due the items being faulty and not tested.
With regards to risk assessment you do this. You basically go into every room you have and look at potential risks to the public, your staff or you. Oils on floor would cause a risk of slipping, action would be to clean it immedietly. Wires on wax pot - you would say action to check these weekly/monthly for example and you would be looking for exposed wire or wear etc.
Everything is a general 'hazard' what you need to do is a form for items on the 'risk' list that you would need to do/check dailey, such as spillages, fire escapes being blocked. Weekly could be lighting in rooms or on any path clients would use, and monthly could be worn carpet, wires, beds etc.
Its also good to call your local fire brigade and ask them to come and do an assesment on fire risks too. They for free come round and highlight your dangers and also propose safety advice.
There are books you can buy on this from amazon.
Hope this helps for now. Dont panic too much its all easily done.
Kate