unknown BB type

Restoring an old Malvern Star womens bike for a friend and just pulled out the BB to find it is something I’ve never seen and isn’t even mentioned on Sheldon Brown…
Square taper, looks like normal diameter (I should check that one) but there are no threads in the frame. BB slides in from the drive side, to stop it spinning there is a notch in the shell on the drive side that mates with a tab on the outside face of the BB. A deep lockring screws onto the other side of the BB and locks it into the shell.

Anyone seen one before and have any ide where i could get a replecement?

Self contained unit and I can’t immediately see how I might crack it open to service it.

That is a unique ‘Malvern Star standard’ BB. No longer made but you might find a replacement in a good old shop.

In any case, you should be able to open it up and replace the axle if necessary, it uses loose balls.