"The decline of industry since the 70/s is well documented, as are the causes. "
The decline of industry is not at issue here, what is is what are these "feet" that Britain are going to stand on when it leaves Europe
It's already been established that the system we live under is in decline - "going it alone" while at the same time blaming immigration for a natural decline in a moribund system only acts as a diversion (pretty well as your irrelevant points are acting as a diversion to this discussion).
The E.U. is a gathering of States living under a dying system - together the fall might just be a soft one when it comes, as it inevitably will
We can already see what "going it alone" is likely to produce
We already have a sharp rise in racism, Trump's flag waving militaristic threats have moved the atomic clock nearer midnight in the short time he has been in power
The ultra-right are on the move again, it is no accident that, in Europe they are aiming to destroy the E.U.

Add to this mix the Oil Wars that have established the poorer nations, not only incited by West, but armed by them, which is leading to a rise in religious fundamentalism
If Global warming wasn't enough, ll this is leading to a planet unfit for Human habitation
This is the level we need to discuss - not crappy blogs by a career blogger who has turned blogging into a self-serving cottage industry

"Your huge chemical dumping grounds are a figment of your imagination."
I don't expect either a withdrawal (not your thing apparently) but

https://chemicalwatch.com/69212/no-deal-brexit-could-make-uk-chemicals-dumping-ground