[Dovecot] OT: Counting emails in IMAP folders

Greetings

I have a customer who has mail server running dovecot with an IMAP account (Customers) which contains hundreds of folders (one per customer).

Looks like this:

Customers Fred Smith and Co Joe Blogss Cust-1 Cust-n

They have a requirement to report monthly on the total number of emails added to each customers' folder during the month.

Basically I need to be able to run some kind of command line query that will give me each of the sub-folder names and the number of emails added to the folder for that month (or other user-specified time period).

Any ideas please?

TIA

Nigel.