Aye, Business Link would definitely be a good bet,
Business support, information and advice | Business Link
Also (and this is coming from someone who is self-employed but not running a salon), I'd be inclined to do some financial planning, e.g. work out how much it would cost to rent a salon, plus things like business rates, utilities (gas, electric, water, phone, etc) - these will be expenses that will need to be budgeted for each month and probably won't change that much on a month-by-month basis.
Then work out which treatments you would offer - and you'd need to factor in things like the time taken per treatment, the cost of products, etc, per treatment, and the amount you would charge the client. This should then give you a rough idea of the profit you would make per treatment.
However, the chances are that your salon won't be 100% booked all the time, so you'd need to calculate a "break even" figure for how busy your salon would need to be to cover its running costs. Also the chances are that you would end up making a loss for the first few months while you build up a client base - so make sure you have sufficient funding to cover this period, either from savings that you would be prepared to invest in the business, or from borrowing money, e.g. a bank loan.
Then there are other expenses you would need to consider, e.g. insurance - you'll definitely need public liability insurance for starters, plus if you employ anyone, you'll need employer's liability insurance, then you'll also need buildings insurance for the salon (check to see if this is included in what you would pay as rent though) plus you'll also need to insure all your equipment and products too.
Then there are things like marketing, e.g. flyers and leaflet drops, advertising in the local paper or on local radio, website design, etc - and marketing will be absolutely critical in your start-up stage, as you'll want to build up your client base as quickly as possible in order to minimise losses and start turning a profit. You could consider things like offering clients an initial discount on their first treatment, or getting a discount off their next treatment (or a free treatment such as a manicure or eyelash tint) for referring their friends to you for a treatment - also consider loyalty schemes, e.g. for repeat treatments such as waxing and eyelash tinting, you could offer every 6th treatment free, for example.
Also don't forget things like accounting - how are you going to do your accounting and budgeting? Are you going to hire an accountant to help with that side of the business, or do it yourself, e.g. using an accounts package such as Sage, QuickBooks, etc?
Then there's the tax side of things to consider. Will it just be you working at the salon, or will you be employing anyone else? Will you be working as a sole trader, a partnership, or would you start a limited company? The tax regimes for each are different, and you'd be advised to speak to an accountant or tax adviser to work out which would be best for you.
Hope that helps - and hope I haven't forgotten anything
