Wow. The Excel file from the ONS shows 98.5% of people age 80 and above are boosted. That leaves hardly anyone not boosted or not vaccinated. The population 85+ years old is 1.6 million:
Multiply by 1.5% gives 24,000 people. A very small data set. I expect only a small fraction of that is "not vaccinated." A few thousand? You cannot draw many conclusions from that. I'll bet they live in the middle of nowhere. They must be very healthy old geezers, or they would be dead from COVID. Very healthy or very lucky.
Jeffery Morris wrote a number of papers taking a close look at the UK COVID statistics. Such as this one. He described some statistical anomalies caused by the small data set.
Two comments:
1. This newspaper article may have a base rate fallacy. They should have presented per capita death rates.
2. This graph from the UK shows that old people must get booster shots! Look at the 80+ group.
https://www.health-ni.gov.uk/sites/default/files/publications/health/doh-vaccination-status-weeks-03-06.pdf