Octatrack MK1 Replacement Parts

Hey All, I have an Octatrack mk1 with a couple of faulty buttons. I have replaced a few encoders on it a few years ago and I’m more than comfortable doing it myself. It was fairly easy to find the encoder part numbers on Mouser, but I can’t seem to find any info on the buttons. Does anybody happen to have the part number?

Reached out to Elektron, but it seems like a lengthy process with them.
Any help would be much appreciated.