New clutch abutment circlip (06-0752)?

Yes it is 

You might consider the circlip used on the MK3 anti-backfire assembly.

06.8072

It needs a light lick with a file to fit in the groove, but is far more robust and gives significantly less clutch basket wobble.

https://andover-norton.co.uk/en/shop-details-2/17464/circlip

Yes indeed, it's tighter on the shaft, a little thicker (hence the need to file) and has a flatter face that prevents the clutch spacer from rocking as much.

I've done a few like this now, and am pleased.

I followed Grant's tip and ordered the 06.8072 circlip. Having attempted a trial fitting I now see why Andover Norton invented their fitting tool.

However, the point of this post is to document the state of the standard circlip that I found when surveying my dismantled clutch. It would seem that a previous owner believed the workshop manual's advice about torquing the nut to 70 ft lb.

As can be seen above, a sharp step has been formed where the spacer has been forced against the circlip.

There is a corresponding step in the opposite sense on the reverse side, where the circlip has been forced back over the lip of its groove. This can be seen in the following picture, showing the circlip in situ in its recess in the spacer.