None of the things you mention are things I've seen in my union covered jobs in the UK.
I've never heard of union rules here. Employees are not required to be part of the union in order to get their benefits, the unions just negotiate with employers on behalf of all employees. I've also never heard of credentials/gatekeeping for unions in the companies I've worked in.
For reference, I was working as a software developer at a University on a research project: I got the benefits of the higher education university (nationally negotiated pay scales, holiday benefits, etc) but was not a member.
Pay was lower, yes, but that wasn't mandatory; that was just the budget of a research project.
I've never heard of union rules here. Employees are not required to be part of the union in order to get their benefits, the unions just negotiate with employers on behalf of all employees. I've also never heard of credentials/gatekeeping for unions in the companies I've worked in.
For reference, I was working as a software developer at a University on a research project: I got the benefits of the higher education university (nationally negotiated pay scales, holiday benefits, etc) but was not a member.
Pay was lower, yes, but that wasn't mandatory; that was just the budget of a research project.