Rover owners: Wheel nut replacement

Hi,

My wheel nuts are getting pretty worn. I have the nuts that have multiple slots down the main part of the nut, as shown in the attached picture. The edges to the grooves are well worn down. The socket is now starting to stick onto the nut clearly indicating the socket is starting to slip.

I would like to replace the nuts with a new set. The nut has M12 x 1.5 written on the side.

Is there anything I need to be careful of when buying a new set?

Any suggestions of what I should buy and where from?

A quick look at Rimmers does not show these multiple slotted nuts.

Thanks!

Attached Images