It's 1 1/16" - which is also 27mm....
It's the same axle. If you have good karma or are very lucky, it broke out at the hub and you can just grab it with channel-locks and slap in a new one and be on your way. Usually, though, they 'explode' inside the diff which you then have to drop to retrieve the stub. The spider gear keeps you from shoving a tool in from one side to whack the offending part out. You do want to get all the swarf/detritus out....
If you got an axle from 'somebody' it's probably on old one. The workshop manual suggests replacing both axles if one breaks, since there's probably damage to the one that didn't break. Which is the one you got from someone. (Long time Rover owners usually have a garage-full of old axles.) Buy a pair and do it right. Your Rover will thank you.
A tip: scratch a line down the axle shaft with the tang of a file. If you ever pull the axle in the future and find the line is twisted, it's an indication of stress and potential failure.
Cheers
