If her costs are anything like they are in my area she needs to tread very carefully.
In my High Street’s small shopping centre there is a single shop to let (about the size that would accommodate three chairs were it a hairdressers. The business rates (2018-19, no doubt more this coming year) are £11,880. The rent is £22,500 + VAT per annum (I’ll assume the VAT is recoverable). This equates to £661 per week. That is the amount your daughter will have to take before she has anything left to pay: Energy bills; water charges; business and public liability insurance; laundry; materials; depreciation (of tools and equipment); quite a few things I haven’t thought of; and I nearly forgot – a bit of wages for herself. That’s a £110 a day that must be taken – each and every day – to pay rent and the council. She will be collecting £38 a day to hand straight to the Council (and for that she will not even get her bins emptied) and £72 a day (possibly plus VAT is she does not register) for the landlord.
It is little wonder that High Streets are “dying”. Your daughter may be in a better position than most if she can rent a chair or two. But for normal shops – especially those who have to employ staff (c. £60 a day plus employers’ NI contributions) the costs involved are simply prohibitive.