Some positive herd immunity-related content from the ONS.
https://www.ons.gov.uk/peoplepopula...rveyantibodyandvaccinationdatafortheuk/latest
Nearly everyone over 50 tested positive for antibodies 3 weeks ago, either vaccine or infection related, and 90% of adults overall. Big drop off from 35 downward, as those groups have only been getting jabbed recently. Interesting that the 16-25 y/o were at around 20% pre-vaccine, which should help make up for lower vaccine take-up in that group.
The big unknown is the pool of under-16s, since they're not in the survey. They're not vaccinated at them moment, so will have lower levels of immunity. Although if you believe Indie Sage, schools are swimming in Covid, so they'll have generated some antibodies that way.