Does any government dept release info on the number of people who have not left UK in accordance with their Visa terms. Over the years I have known of quite a few who have exceeded their visa stay and were working cash in hand. Recently there was a newspaper article, can't recall which, discussing the proportion of foreign students from China as being 30% of total. Concern in article was that a lot of them are coerced into spying for China, being well funded for all costs. Wonder if this is also going on with other countries.
As to immigration, try getting into Canada, USA, Australia because you have family living there.!A neighbour who has a son and his family living in USA. At one time her husband was working there . Applied for Visa to visit husband, refused on that occasion, why, she had been out 3 times already in the previous 2 years visiting son and husband. Husband had to come here for his holiday. A lot of countries have qualification needs or skill requirements before being allowed to immigrate. Why has UK to be different?