Oh my! Such varied views. Some of the following may not be relevant to the original poster but I hope it helps.
What councils are worried about (apart from claiming any extra rates they can get their hands on!) is whether the footfall (people visiting your salon at home) will impact on the neighbours and environment such as parking space and extra deliveries; and also any logistics regarding waste disposal. It is not scary or difficult to sort out and do your initial enquiries semi anonymously so that you can get an idea of what their issues might be, and what you can solve to make it easier and cheaper for you. For example, it could be that if you retain a lovely couch, that also happens to be a sofabed, in your salon, so then it might be there are no extra rates as it is a "spare room". Worth a thought and asking the question!
You need to look into your your deeds or rental agreement. There could be a clause that prohibits work at home. But some of these clauses were written in the dark ages to stop smelly animal rendering and glue production and other such activities. Again they may also be there to guard against the impact on neighbours with footfall and deliveries etc. Don't stress over this and it may not be as difficult or impossible as it may look to sort or work around.
Your mortgage company may need to be contacted but quite frankly, unless there was a serious reason why you could not have a salon at home I tend to think they would rather you maximised your income potential so that you can pay the mortgage. Again do not stress over this.
Also to take into account if that salon is exclusively a salon then you may be liable to capital gains tax when you come to sell. Just ask your mortgage broker or a property/financial expert. But we are not talking about selling your soul to the devil, it is a matter of a % of profits from the sale and nothing to be scared about.
And then there is the chestnut of insurance. With some home-based businesses you may find that your insurance goes down simply because you are at home and are a deterrent to burglars! Just phone then up and ask them! No charge for just asking. And ask around different insurance companies for quotes and change if need be. Insurance may go up but this might not be as much as thought as it is balanced against you being at home.
And if you are mobile based then inform your car insurer. I am mobile and was rather chuffed when I contacted my car insurer to find out that I could be covered for using my car and carrying my stuff and that it was no extra cost. In fact, I did it at a time when my insurance was up for renewal and my broker found me an even cheaper rate so mine went down!
When you are working mobile, I understand that you can bag up the waste you produce and give it to them to include in their household rubbish. So you are not producing loads of waste that you need to dispose at your own home. I am not 100% sure what the position is regarding the higher risk waste but I give my clients own wax waste that includes slight blood spotting for them to include in their rubbish and am under the impression that is OK. After all, if you cut yourself at home you clean up and dispose in the normal way.
Now. Do not take my word as gospel on any of the above as rules and regs vary from county to county and country to country. But there are a few pointers to ask.
I hope that helps!