This is obviously not a comprehensive list and no doubt some people here will know many of the answers. But at the moment it feels like we are being fed folk tales in the place of facts.

But while employer contributions are so advantageous, either <everyone> or <no one> should have the chance to be paid into their pension outside of pay

SS exists because employer pension contributions are much more tax supported than employee contributions.

Really they should be treated the same, as low earners tend to get more in employee contributions, high earners in employers’

(one of many ways pension tax relief favours the high paid)

There's a link between the two as well... higher take-up of benefits translates into a higher income deprivation score, as it is a count of benefit receipt not eligibility.

16% is a bit misleading. Probably something roughly like 65% of 200k+ members and 5-9% of 800k affiliated orgs/mainly unions, where people didnt choose to join. They split the turnout by category every other time

Thanks Giles!