Just to put down here what I've done as it all went successfully.
After making a backup I renamed the domain:
I then check the notebook account as suggested in the bug report:
zmprov -l olddomain.co.uk newdomain.co.uk
So I then ran:
zmprov gacf | grep Notebook
zmprov mcf zimbraNotebookAccount email@example.com
Once this was done I logged into the admin interface and set the new domain to be the default under Global Settings.
Now I created a new domain with the same name as the old one and aliased it to the new one.
zmprov cd olddomain.co.uk zimbraDomainType alias zimbraMailCatchAllAddress @olddomain.co.uk zimbraMailCatchAllForwardingAddress @newdomain.co.uk
After running some tests sending e-mail to both domains separately I can confirm that this method worked fine and I received both e-mails.