I hear from some people that when selling a large amount of Bitcoin and having that money hit their UK bank account, the bank has froze their money or notified them they will close their account.
Other people say they had no issues and no one has said anything.
Have you have any problems and more importantly who gave you the best rates and was the least hassle to deal with.
The banks have algorithms that get triggered when unusual amounts go through a person's account.
Withdraw your money in small amounts (under £500 a time), vary the amounts, and withdraw to several different banks.
And pay tax on your money.