From the BBC:
"However, specialists say that flying into a foreign city for an operation means that patients are not properly assessed prior to surgery - and not given the right support afterwards.
The majority of the 299 people polled by Which? said they were very satisfied with their treatment, but more than a quarter said they had not received the right follow-up care after their procedure."
Some people travelling abroad for surgery are seeking cosmetic surgery but many others are not. If they didn't have to pay twice for their medical care (once for the NHS, once to get the operation within a reasonable time and without a huge risk of serious infection) then they might not need to leave the UK. While there is every reason to believe that standards abroad are generally excellent there are risks to travelling for surgery, in particular the inability to integrate further care before and after the operation.
If we learn lessons from other European countries and create a less centralised, more competitive healthcare system that isn't run by politicians then fewer people might feel the need to take the risks associated with health tourism.