I can’t recommend an accountant cause I do my tax returns myself (pretty easy, have a look online for some samples)
I have a sole trader account with Starling, can’t fault them at all BUT it does say before you set it up that they don’t support dating/escort services. I’m not registered as an escort with HMRC I’m down as something else cash based but that means I can’t put my hotel bookings through my business account or on my expenses without raising questions.
If you are going to register as an escort read the T&Cs on your account first cause they can close it on you, I’m sure someone who has done this will comment soon which will be more help to you.
HMRC have a YouTube channel that is pretty good