Well you can 'avoid' registering for tax and some people do, but we're not going to help you do that here. That said, if it's a working holiday you might declare it with your normal income in your own country - I did this when I worked overseas.
I'm not quite sure what you're hoping for; your posts read as if you plan on charging very high rates that only a tiny proportion of punters will pay, and this is going to take a massive marketing effort (although if you can spin it as a very limited opportunity to see you while you're here that could work) for relatively few bookings and you're really limiting yourself to London and possibly Edinburgh. It really depends on how much work you want and how much free time plus your costs - if you're planning to offer incalls then you'll need somewhere plush and that won't be cheap.
There's a thread here that might be useful too; I remembered it this morning and I think the poster is still about https://saafe.info/main/questions-and-answers/new-starter-marketing-high-cost-outcalls/
Very dear Amy, it's so reassuring to notice that here I can get so much help and useful advice! I couldn't ask for more!
Well, I'm not planning to be a "tax-cheater" nor I expect you to be my accomplishes!
What happens is that in Portugal escorting isn't considered an official source of income, and here all our moneys from that activity aren't declared by anybody!
So the money I would gain in UK I can legally avoid to declare in this my own country!
You guessed it right, I do plan to ask for higher fares, and offer exclusive services, mainly overnights.
My idea is to avoid incalls at an initial stage, and concentrate on opportunities like spending long hours in a luxury Hotel room with a wealthy visitor, perhaps a foreign businessman or tourist.
So, you're right, London and/or Glasgow/Edinburgh seem the obvious choices.
Perhaps Manchester and Liverpool too?
I know I'm probably going to encounter many difficulties, but if I don't try I'll never find my way...