I was investigating myself. For me the best way actually seems to just give a Unionpay debit card from a Chinese accont to a trusted relative back home. Unionpay cards since 2013 are accepted at all 'Link' ATMs in the UK and there are thousands of those everywhere, the transaction fees seem low and the exchange rates seem fair. Then my trusted relative can simply keep the cash to spend for themselves and pay credit into my UK account.

I'd rather there was away to do everything myself and not involve anyone else..but that seems impossible.