I needed something similar only last week: I asked at the repair shop (run by a guy called Wes) just off The Cut, he rummaged in a box for me, would take any money for it just told me to donate to his charidee box. I ended up using a normal nut not one of those, but i have a funny old english axle. Worth a try, though i don't know what it's called: on a road just on the north side of the Cut around the Southwark tube end of it, look for the bonkers long surly passenger bike thing outside. Nice bloke.
I needed something similar only last week: I asked at the repair shop (run by a guy called Wes) just off The Cut, he rummaged in a box for me, would take any money for it just told me to donate to his charidee box. I ended up using a normal nut not one of those, but i have a funny old english axle. Worth a try, though i don't know what it's called: on a road just on the north side of the Cut around the Southwark tube end of it, look for the bonkers long surly passenger bike thing outside. Nice bloke.