IIRC para (ii) was added to stop the situation where someone with a SGC would turn up, say, on a bought day’s shooting and lend a shotgun to a fellow gun who did not hold a SGC. The same could be true with a rifle - e.g. a visitor without a FAC is a member of a party staying on an estate in Scotland, he and another member (holding a FAC and who has bought his rifle along for the trip) go out with the guide to stalk deer, and both share and use the same rifle.
In each of the above examples both the lender and the borrower would be breaking the law, as the estate rifle exemption only applies if the lender holds the shooting and/or stalking rights, or has written authorisation from the person who does hold those rights.
Therefore to avoid breaking the law para (ii) was added so that the holder of those rights could issue permission to the lender to loan the rifle/shotgun.
This is why “or” sits between para (i) and para (ii).
If you are a lawful sporting tenant, or have written permission from the landowner to shoot on the premises, then you are deemed to be the occupier and you are already covered for the estate rifle exemption by para (i).
It is nicely explained here:
angliasporting.co.uk