Apologies to everyone who knows this.
The turning 70 stuff isn't correct. The countersignatory must EITHER work in or be retired from a recognised profession or be "a person of good standing in their community" and have a UK or Irish passport if the applicant is applying in the UK. If outwith UK, EU, US or Commonwealth passport.
The official website has an indicative but not exhaustive list of recognised professions. In all cases the countersignatory must have known the applicant (or parent) for more than 2 years and are confident the applicant (or parent) is who they say they are.
Doctors are excluded unless
coincidentally they know the applicant as a friend. You cannot pay a UK solicitor, or any other professional for that matter, to vouch for you if the 2 year rule isn't met.
Councillors, librarians, vicars or any of the other randoms mentioned on here who fail the 2 year rule should not be signing.
The passport office do check. It's a serious criminal offence- isn't that obvious?
A "person of good standing in their
community" is any person who has a reputation to lose. Dinner ladies and lollipop persons are every bit as acceptable as any of the professions.
And again apologies to those who know all of this but there's so much misinformation on here.