Roland SH-7 4 position switch?

Got a Roland SH-7 with a broken 4 position switch that is hard to find. Its the waveform selector rotary switch, 12 position and seems to be a 3 pole, 4 throw.

From the underside, looks like this:

None of the modern 3 Pole / 4 Throw switches have the right (notched) fit that this needs.

Any ideas here would be great, thanks in advance!