Who emmigrates?

Yesterday I mentioned in my post that more people emigrate from the UK than immigrate. After looking at the post again, it set me thinking.
Two of my uncles and aunty's went to Australia in the 60s, possibly on the £10 ticket, my other aunty and uncle who live abroad moved to France after my uncle retired. Similarly my sister's in-laws, sold up and retired to Spain. I have a half cousin who lives in Switzerland, and he's part of the "brain drain", he went there to gain a better paid post. A friend's son lives in Greece, again, he couldn't find a suitable post using his qualifications here in the UK.
When we lose these people in that way, they don't often come back to the UK, apart from visits. So we lose the next generation of that family, who may be as intelligent as their parents. A true "Brain Drain".
However some of the immigrants are bringing their education into the country. But we put up barriers against them using their qualifications.
Teachers who are qualified in the country of their origin are only allowed to teach as unqualified teachers, unless they complete ITT...again...to our standards. [An unqualified teacher can only teach for 5 years, the idea is they qualify within that time.]
One immigrant I know is a civil engineer in his country of origin, but has taken a much lower level post here, just in order to get a good standard of living. Also my Mum's current dentist is from Poland, as our NHS dental service seem unable to keep hold of enough NHS dentists. I'm sure Mum's dentist is just a proficient, but we still have people training as dentists here, only to either emigrate as soon as possible, or go into private practice.
Ironic isn't it?