Not so. If you're a "nail tecnician" but your spending deductibles are condoms, hotels and fuel it might raise an airbrow and you can get called to clarify this. I would try to choose something more "accordingly" like maybe outcall massage therapist?
The only time HMRC will see the actual breakdown of what your expenses are is if they choose you for a random audit and you have to detail it all with receipts etc. They do not check tax returns in any detail when submitted. At the point of an audit you would then fess up to what you actually do, but as long as expenses are for items used for your actual job they won't care what you have put down as your job.
They would only see at first sight turnover less expenses, which are grouped under headings, like utilities, goods etc not individual items like condoms etc. Expenses for hotels etc would come under accommodation, so that could be a shop or anything, they would only know the ins and outs if they audited you and as I said that is the point you would fess up anyway.