Steve.. glad you got the scope you wanted mate. There very good.. and I'm jealous
The way I got mine sorted on the Remy was to mount it in my cleaning tray, making sure it was as close to level as could by eye. Then I placed a small spirit level on the elevation turret at right angles to the scope and, with the scope in the rings but loose enough to move, just jiggled it around until the bubble was dead centre. I think you'll find that once you have the horizontal the rest will be true too.
I tried this some time ago, when I knew nothing, by trial and error and with the rifle mounted up and down to my shoulder...!!! Needless to say it don't work very well at all.. if at all..
Hope this helps mate.