Because of the high vaccination in the higher age groups, small errors (2%) in total population (it is overestimated by MIMS because this counts all GP registrations and people often leave and never re-register) result in large errors in estimated unvaccinated population, hence changing the statistics.
Can you stop this nonsense, that has been produced for idiots? This table is about cases among vaccinated/unvaccinated. The group age 40..80 is > 40% of the UK population. If 2% of 40% are missing how much is this?? May be look it up in your undergrad textbook!