The problem with many of those unions was just that they depended on industry that no rational country could have continued to run forever. Like are you seriously going to just continue to mine coal forever, in mines that have been active for 100s of years and were just losing money.
The leader of the coal miners union didn't even fight for coal minor wages, he was talking actually revolution.
Some privatizations were sensible, lets remember that Nordics, Switzerland and so on also did that and you can do it well depending on the situation. But they are complex issues that you need to consider rationally on what you want to do.
The British government rail was probably to big, doing to many things and selling part of that and splitting it up and opening it up to some competition is sensible.
In my opinion labor in the 1950/1960 just did poorly, overly focus on some of their socialist hangups rather then making smart policy. Like Britain had debt after the war for sure, but its not like it was bombed to the ground (the Blitz was minor compared what most countries experienced), you have a rebuilding Europe. Britain had a world class aircraft industry, advanced nuclear, building lots of cars, world leading and so and so. Its had a great good electronics sector as well. Being among the best in the world in almost every major technology.
And somehow that couldn't be leveraged into much economic success. You have terrible growth and massive inflation just 20 year later. Something did go wrong, and you can't blame the conservatives. Even when they were in power for period they only slightly slow down the agenda.
To be sure, good things were done in that period as well it certainty wasn't all bad but its hard to look at pre-Tracher Britain and be overly impressed.