They had some old stock ones yonks ago. It is a particularly nasty little sod to shift. Very often previous owners have been in a mucked the thread up, which is very fine. That then destroys the puller. Interestingly the factory one has a very long length. I wondered if it was so you could removed a few mm of lost/damaged thread to get more use from it!
There is a way to get round having the tool. Not ideal, but it can be done. I have had to cut this gear off with a grinder before now as such a mess made it impossible to pull off and useless leaving it in situ.
Effectively you remove the chain from the gear, having undone the collar fasteners, and pull off the chaincase. There is just room to do this by spreading the chain round the edge of the top sprocket, having removed the bottom chain wheel. You may need heat to loosen the collar, which is a tight fit with no obvious place to lever it off. Be sure to have the LH thread nut loosened off, as you will be left with no leverage to lock from rotating later. With the chaincase off the trapped collar exposes enough of the top sprocket to get a three leg puller, or what you might have suitable, on it. It is on a taper with keyway. Wind on tension and then sharply tap the end of the puller baring on the shaft to brake the fit.
With the sprocket off you can remove the swivel with its interior bearing and oil seal.
