I agree with you that the retirement age of magistrates needs looking at. I believe it is a perfectly reasonable position to suggest that as life expectancy has increased, we should discuss whether the mandatory retirement age for judicial office holders needs to be raised.
As you may know, many judges, below the High Court can already be authorised to sit past the mandatory retirement age. This is permitted when there is a public interest. However, as it stands, this does not extend to magistrates. Primary legislation is required to amend the mandatory retirement age or to enable magistrates to sit for a temporary period of time beyond the existing mandatory retirement age where there is a business need.
For this reason, the Government has published a public consultation on proposals to raise the mandatory retirement age for most judicial officer holders. I am glad to say that this includes magistrates. The consultation closes on 16 October 2020 and the Government will publish a response in early 2021.
I would encourage you to make a submission to the consultation, you can do so at this link: https://consult.justice.gov.uk/digital-communications/judicial-mandatory-retirement-age/.