The first question is. Why are you wanting to change your current rear axle? If it's just because it has drums, then that isn't really a great reason tbh. And you'd be better served making them work as they should. In working order they are more than up to the task.
As for the axle itself. The 110, has a higher pay load rating and potentially can tow more (although restricted by UK laws) than other Land Rovers. But when used for certain commercial or military uses, is likely to see more punishment than a 90 or a Defender.
So Land Rover used a beefier, bigger stronger axle on the rear. On older 110's this is a Salisbury unit and shares nothing with a regular Rover axle. It's actually based/copied from the Dana 60 axle, which is an American axle found on lots of American pickup trucks.
The Salisbury is a very good axle by and large.
Latter 110's stopped using the Salisbury axle, I suspect due to political and cost reasons. Not because it wasn't needed. These latter 110's used a variation of the p38a Range Rover axle. This axle is a Rover based one, but a stronger variant. However I don't believe you can simply swap on a p38a axle, as the mountings are different.
A Discovery/RRC/90 axle will have the same mountings for a 110 and will physically fit. But the axle is far more likely to fail in a 110 than it is in the others.
This isn't to say it won't work. Chances are it'd be fine. Because you are only dealing with a single vehicle. But from LR's standpoint where they made 1000's of 110's a year, the Disco axle would likely have caused lots of warranty repairs, as it would have a higher rate of failure.