I can't help thinking that BASC are presenting a one-sided view, as they sometimes do.

As an adult I'd like to be presented with a link to the source figures, as well as the BASC take on them , so have gone off to find this for myself.
There hasn't been time to look at the detail yet.
The Home Office are saying that all new applications for an FAC, SGC, or co-terminous received up to 31st March 2022 were processed and completed.
There has been quite a jump in Revocations, and Applications Refused, and firearms stolen.
I know of at least 20 people who've given up after the long lockdown, including a few who've died.
The medical clearance requirement has added to the delay, explained officially as;-
A range of restrictions relating to the COVID-19 pandemic began on 12 March 2020, and the first UK lockdown measures were announced on 23 March 2020. Some figures presented for the previous year (year ending 31 March 2021) will have been affected by this, particularly those relating to new grant applications and visitor permits. Whilst most comparisons with the previous year have been retained as a valid measure of change over the period, changes should be considered in the context of the pandemic and treated with caution.
www.gov.uk