If that's a Novatec lock nut (and it looks a lot like the Novatec lock nut I have in my hand) then I have spares. £5 for a pair posted, PM me if you want them.
Alternatively, the lock nut off any cheap Shimano rear hub will work, although they are mostly 5mm thick so you'll need an extra washer to get the OLN back to precisely 120mm.
If that's a Novatec lock nut (and it looks a lot like the Novatec lock nut I have in my hand) then I have spares. £5 for a pair posted, PM me if you want them.
Alternatively, the lock nut off any cheap Shimano rear hub will work, although they are mostly 5mm thick so you'll need an extra washer to get the OLN back to precisely 120mm.