I have had a message (strangely only once and not again) saying:
"You have reached the maximum allowed limit for Filter based Email forwarding.
Go to Settings >> Email Forwarding and POP/ IMAP section to manage the email addresses added for Filter based Email Forwarding."
I have done my best to find mention of this "limit" anywhere in the sales / help and forum texts and can't find a match.
So, is there a limit to 'filter based email forwarding'?