Dear client, I see you have not had the opportunity to answer my questions. To work as a freelancer or self-employed in the UK you only need to be resident and have the right to work in the country and have your National Insurance Number (NIN).
Then you must register with HMRC as self-employed. As for taxes, if you do not earn more than 6,475 pounds a year, you do not have to pay anything.
If you earn between £6,475 and £9,500 a year you would be considered Class 2 and then you would have to pay £3.05 a week. That's where the £12 a month comes from, which is the only thing many people have stuck with.
If you earn more than 9,500 pounds a year you would be considered Class 4 and you would pay 9% of the profits you earn between 9,500 and 50,000 pounds a year and 2% of the profits over 50,000 pounds. That is to say that if you earn 60,000 pounds a year you would pay an average of 320 pounds a month in fees.