@Gerry @James Ainsworth thanks for that, very useful.
There is only one "To" address but I changed the syntax to LIKE anyway, but still not working.
Not sure if there is something wrong in my config, though its the same I use for other rules (but my only one using ToAddress).
The only other thing that is different is that I have multiple mailboxes, and this particular rule is expected to affect just one of the mailboxes.
Do routing rules get applied to all mailboxes, or is there something extra I would need to do?
My config below (and attached):