CRT just mailed me to acknowledge that a print batch of approx. 40 mooring renewal reminders didn't go out for renewals due in September. This was following my query.
In fairness to them, there was no dispute, I raised it following getting the final invoice and realising it was too late to take advantage of the early payment discount. They looked into it and came back with the news that there had been a problem with a printer - and they've had queries from other affected licensees.
If you're one of those affected, you should email waterside.mooring-enquiries@canalrivertrust.org.uk