The NHS is running out of money because it's been underfunded for like a decade. This means they're cutting things like screening programs. They're also cutting the cervical cancer screening down to 5 years because of the HPV testing programme, which checks for HPV without checking for cervical cancer specifically (HPV causes over 95% of cervical cancer):
The HPV vaccine is offered to Year 8s (age 12-13), on the basis that under 15s only need two jabs instead of three and because it's more effective if given before the kids are sexually active (which could expose them to HPV). Even if they didn't get the jab in school, women (and boys born after 2006) can get the jab for free up to their 25th birthday. This is partially on the basis that offering the vaccine to people age 25+ is not considered cost effective, as it would have little impact on a population scale on the rate of HPV transmission.
The reason gay men up to 45 are offered it is partially because they don't get any passive protection from women being vaccinated (which straight men do - they only just started vaccinating boys) and they generally have more sexual partners and so are more likely to be exposed to HPV (which can also cause anal and throat cancers) so as someone else observed they get more bang for their buck on a population scale. For risk categories the grouping is typically "MSM" (the transphobic "males who have sex with males") so they extend it to trans women on the assumption that they're HSTS and have the same risk profile. They're targeting trans men on the basis of the "gay" ones who use their "front hole" to have sex with "gay" men - the number of surprise trans men pregnancies suggests there's probably little protection being used under the misguided belief that they can't get pregnant. So "gay" trans men get treated as MSM and get it up to age 45, but "straight" trans men (ones who don't have sex with men, only women) get treated the same as women.
It's a bit like how the flu vaccine is only free for over 50s, pregnant women and people who only have certain health conditions. NICE/JCVI tends to focus on population outcomes over individual benefit (e.g. a woman who has had no sexual partners by age 26) and the NHS has to rely on evidence based treatment (which is why people like PhilosophyTube reeee that the NHS doesn't give trans women free FFS or boob jobs, because there's no evidence of a significant life improvement after these procedures).