Hi
I'm hair but the business side of things is the same.
You'll need public liability insurance so you're covered legally, there are lots out there for freelancers, a good one is salon gold.
As well as this, remember to add business use to you car insurance policy, because if you ever get stopped, and they suspect you of driving on business, then there is a hefty fine and you can lose your license !
You'll need to contact HMRC to tell them you're self employed, and then in about a year and a half, you'll need to file your first tax return. I know this all sounds like a lot but HMRC's website will tell you everything about the tax side of things.
You'll need to keep records of your income and outgoings related to the business, which is a little confusing at first. If you have no idea about the whole bookkeeping thing, I'd recommend seeing an accountant for some advice, and then from there you can either do your own books, or hire a professional for the job
It seems like a lot but it really isn't as hard as ive made it sound ! I'm just not very good at wording things :') good luck !