Thanks for the replies.
Yes it is just the bottom part below where the nut rests, a 'V' section has been broken out welded and cleaned up. The lug itself is OK.
Are they known to break the casing here and is it a indication that the wrong size nut has been used? Is this a 'special' Honda size nut or just a std 10mm full nut?
Have been provided with some photos of before and after, though do not think it is fair to post on here as it is not my bike.