CGT on Crypto gains made in non UK Country, liable for UK taxes?

Hi Guys A friend of mine is from the UK and has made some money in Crypto and is thinking of going to the Channel Islands (spending some of his time there and some of his time in the UK) and cashing in the crypto when there and sending some of it back to his UK bank account to mitigate the CGT charged in the UK as there is no CGT in the channel islands. Can he do this? I am sure there would be some UK based taxes that he would be liable for would there?. Many thanks

Hi,
It depends on where he is actually resident and as still spending time in the UK, he would need to determine where this is. 
Please refer to:
RDR3 Statutory Residence Test
Thank you.