Looking for this switch (Midas Venice solo switch)

I'm repairing a Midas Venice mixing console. Try and avoid doing so.
It's a nightmare

Despite the agent's tech insisting that the 'solo' switches are 'self
cleaning', no amount of exercising them will prevent 2 of them behaving
intermittently.

They are pcb vertical mount types, i.e. the control surface is a series
of large flat double sided boards. From appearance I guessed the
switches to be ALPS but the German parts list gives the following
reference as best as I can decode it.

SCHALTER-TAST 4XUM 1 switch 4pdt

It's a latching type btw.

Any help sourcing same would be appreciated. I only need 2 but knowing
this beast one or two more might pack up !

Thanks,   Graham