Read the administrators reports about the financial difficulties!
Ah, thanks.
You've just reminded me even the administrators didn't get paid.
https://www.express.co.uk/news/royal/1884151/carole-michael-middleton-party-pieces-insolvency-costs
As for whether the difficulties started with Covid we don't and can't know because partnership financial records aren't made public.
However there have long been questions over how a business whose top priced item retailed at £50 and which was competing against a host of others of similar size, selling similar items and who were turning profits of a decent but comparatively modest £130K or so apparently became a multi million pound juggernaut:
archive.ph/X87Yi