Much depends on what sort of expat you are and if you consider yourself an expat, sure most who go retire in Spain they are just Brits sunning it in Spain for a few years , most do not even speak a word of Spanish, of course they will always go back for their free treatment and pension..
There are also lots of people who simply left the UK years ago and never return, I have several friends here from the Uk who have been here like 25/30 years, they are pretty well Russian, speak fluent, have Russian passports, kids with Russian passports .. going back to the UK for any treatment is not an option or even a consideration. Most Brits I know here consider Russian education to be better than in the UK, and prefer their kids to be educated here in Russian myself included. University is free in Russia unlike the Uk where basically if your from a low income family you will have a chain round your neck for a long long time! Its house loans in the UK its normal to have a mortgage round your neck for 35 years and pay a big chunk of your money to it.
And worst of all in the UK if your earning lots you pay lots in tax lots and lots and that doesn't include all the indirect taxes, basically your ass is taxed till you die..When I left the Uk I only had $50 a week to live on, if I returned now I would be in the top 5% of earners and would be clobbered, I don't work 20 hours a day to fund the unemployed and all other tom dick and harry wanting some form of benefits .
Also Russia and probably many other countries offer chances in life you would never ever get in the Uk. I know lots of people here who have made it fairly big , have no debt and all say they would never of got the opportunity in the Uk. My cousin works and lives in China and also says the same ..it is a common story.
Myself I do not have private medical , I can afford it but have other requirements for that money at the moment but probably in a few years time I will maybe find some private care. Good quality treatment is not expensive in Russia as it is in many other countries, though probably if I woke up with a brain tumor tomorrow I would go back to the UK.. and why not I paid enough taxes and stuff there in my time..why should I pay for it privately ? But of course as time goes on I would not be able to use that excuse..I could hardly use that excuse in 15 years time!
I see it like this.. if your born in the UK with a silver spoon in your mouth, mummy and daddy act as a bank for you then you will never have nothing to complain about , not so many people are though.
Most people are born into hell and have to climb their way out of the shit is the way I see it in the UK, a few more years its going to be just the have's and have nots in the UK..