I am a company secretary for a UK charity.
There are several annual filings that have to happen with different bodies.
OK, I do them online, but even then, I make sure I've had the confirmation email; log in and see that the account has updated; check the register to see what is publicly showing - all to make sure it's gone through OK. We have a very high profile patron, so to have anything amiss that the press could pick up on could be disastrous (not dissimilar to Archewell's position, then...)
I also get sent automated email reminders from the relevant bodies reminding me that things are due, so if for some reason the filing had failed, I would be notified that it was still outstanding.
I can't believe that no one at Archewell would have kept an eye on it or have been aware that they were a year late with their paperwork. So "the cheque got lost in the post" sounds like a BS excuse to me 🤷♀️