I reach retiring age in 2029 but it's by no means certain that there will be a pension by then.

It seems a fantastical notion .. I cannot imagine it. Think about the voting public etc and people that have paid their NI dues ..

At the mo it seems that the government is not collecting statistics on pensioners:

We do not collect or publish data on 'pensioners'; that is, we do not publish statistics on those who are claiming a pension and/or identify as a 'pensioner'.

From:
https://www.ons.gov.uk/census

Am I being conspiratorial by asking 'Why not?' .. and I really .. really, can't see the/a problem : )?