Unfortunately I do know just one source for this special tool; it’s Five Big…
We don’t have such a tool at our workshop in Vienna, but we will get one in a couple of weeks.
But there might be another option…
Could you please measure the biggest diameter of the crank spindle?
I guess that should be the part with the thread (?).
It might be possible to drill out the hole of a common tool “T”, but to be sure I need to know the mentioned maximum diameter.