EU restrictions were never the reason for the decline of British manufacturing, the reasons were short term planning, entrenched management practices, and an unproductive workforce. Germany operated under exactly the same "restrictions". And it's not at is if was all bad in Britain, the country developed a thriving services sector, creative industries, higher education sector, to some extent even high tech manufacturing. And the NHS, which you seem desperate to flog off. The 50s were really not a great time, there was far less access to higher education. And there was far less variety of consumer goods and foodstuffs. People's expectations have risen faster than their actual wealth.

People need to move on. My grandfather was a coal miner. At least 5 and probably more generations before him were coal miners, back to the days of the bell pits. But in the 1920s, with the mines closing in Somerset, he didn't sit about moaning that he had been left behind, he crossed the country looking for different work, and found it as an electrician. His sons didn't get the chance to go to university, because of a mixture of poverty and the war, but they all emphasised to the next generation the value of education, and that they had to look for opportunities and take them, not wait for things to be presented to them on a plate.

The left behind communities will only cease to be left behind when the people in them learn to move on.