Oi. Senga is a nice lady, and I don't think she deserves bumping off!
On the unvaccinated, I'm actually surprised it's that few. I assume some will be die hard tin-hatters, but most will be people with medical issues where the vaccine is not safe, or severe needle-phobics (I didn't realise about 10% of the population have needlephobia which must be so difficult to overcome...) or have some other valid reason why they couldn't travel to the centre or have the jab. Or be under 18, where the jab was initially not recommended, and still marginally beneficial, so I can totally understand those children/ families not choosing to take it.
Also, as far as I know, there is (or at least, was) absolutely no way over 40s can choose which vaccine they are offered. So if they didn't want AZ for any reason, they couldn't choose not to have it... it was that or nothing. So some have chosen nothing. My neighbour, early 40s, had to lie and say she could be pregnant in order to get Pfizer, because there was no way she was taking AZ cos of the clot risk and that was the only thing the centre was offering her otherwise... it's only because she had a "helpful" nurse who suggested that they couldn't give AZ to anyone pregnant or possibly pregnant that she had the vaccine. (though it led to an awkward conversation at her second jag!) I can't imagine that's a huge number, and they may be more flexible now, but it really wasn't a great way of encouraging the slightly wary!
I think a nasal version of the vaccine could get a few more % done, but they've probably looked at that and thought it's not feasible, or too expensive or whatever.