[rdiff-backup-users] preserve-numerical-ids not working as expected

[explosive]

Hi,

I am using rdiff-backup to `push` backups via SSH to another server. Everything appears to be working fine apart from preservation of users/groups.
It appears from the man page that I need to the the --preserve-numerical-ids option in order to keep the original user and group ids. Despite this setting being enabled the backups still get stored with the user & group of the SSH user that I use to connect to the backup server.

Any ideas what I may be doing wrong?

Many Thanks,
Tom