Hi Coralie and welcome
The best place to get tax advice is HMRC - it's them who will be calculating and collecting it, after all. Their website and the people who man their Self Employed helpline are great and couldn't be more helpful - it's a freephone number too (and as has been covered
ad nauseum on various threads already, you don't have to tell them the nature of your business if you don't want to).
I would also say that it's not necessary to find an 'escort friendly' accountant - an individual working for themselves with no employees doesn't present a challenge to any accountant and if somebody in any role or offering any service which is not unique to this industry seems to be deliberately targetting workers in it than it could well be because they think it's OK to charge us more than other people, behave unprofessionally towards us and so on (it's not guaranteed of course, and some will be fine). You are a business owner seeking a paid professional service and the nature of your business is irrelevant.