I think, Guilbert53, that for the most part, the people who leave the UK, are retirees, who move abroad, buy a property outright, don’t need a job, and put money into their chosen country’s economy.
I don’t think too many Brits who go to Europe, expect their chosen country to house, educate, provide heath care, and live off the indigenous people’s taxes.
It is estimated that there are 1 million Brits living throughout the whole of Europe, but 3 million Europeans living in the UK.