I have applied for and been accepted for a new job
Do employers carry out routine health screening and are they likely to reject me as I might
well not qualify for a life insurance scheme?
dunno. pre-employment health screening seems to have got less rigorous in the last few years (whether it's shortage of medical professionals / cost of actually sending people to see a doctor / post-covid stuff, i'm not sure) - i've had one where it's been something like a question 'do you have any health conditions you think might affect your ability to do this job?, if so give details' and nothing further if you say 'no'
what have they actually said so far - is this a provisional offer subject to references, health clearance and anything else like that?
general wisdom is you don't start giving notice on current job when it's still provisional.
subject to all the usual disclaimers that i'm not a lawyer etc -
as others have said, they should only ask at the application stage about whether you need any adjustments for the interview.
the equality act (which has included the disability discrimination act) says that employers shouldn't ask health questions before an offer - and after a provisional offer, there needs to be good reason for withdrawing an offer. an obvious example from my line of country would be someone might get a provisional job offer as a trainee bus driver, but their medical shows that their eyesight or a health condition means they would not get a bus drivers' licence from DVLA, in which case it's lawful for the offer to be withdrawn.
there are employers out there who haven't really got the hang of the 1970s sex / race discrimination laws, so there are employers who will come up with a reason to withdraw an offer if a health issue comes up, but they are possibly open to a tribunal (although that comes down to what you can prove)
i'm not sure about life insurance schemes - if this is something that's seen as a benefit / discretionary thing, then it may have its own conditions but that shouldn't stop you being offered the job, even if they impose some special conditions on the life insurance bit of it. i'm back in local authority now, and the pension scheme includes a life insurance element - i can't remember now if i had to do a separate medical questionnaire for that, but it wasn't anything that drastic.
i also understand that you can't claim protection under the equality act for disability discrimination if you don't declare something. however, you do have unfair dismissal protection from day one if it's on equality act 'protected characteristic' grounds.
hope all goes well.