An obvious answer: make the penalties a % of turnover or profit, with an exception where the directors file a sworn statement explaining the reason for the delay.

a percentage of turnover

Our list of delinquent PLCs is here. Listed companies highlighted in yellow. There are some very strange companies in the list. We'll be reporting in detail on one of them soon. https://taxpolicy.org.uk/2024/08/10/list_of_plcs_that_have_missed_accounting_deadline/