It's Roland/edirol part number is SSSF124-S09N-0 double check the service manual which is available online. It doesn't match any external parts but I didn't look to deeply. Probably best to desolder it from the board if its broken and either look for a number on the part or find one that is equivalent

Wow thanks very much for that quick response, was not expecting one that fast! Ok thanks I will do a check of the service manual and can remove and replace. Yes looking it seems I would probably need to desolder and check as that part doesn't seem to correspond to anything other than roland, thanks for advice.

Is the switch physically broken or just not working?Might be worth giving it a shot of Deoxit contact cleaner. Not sure if you'll be able to get it inside of it but worth a shot if it's just got some contact oxidation.
I'm no expert so take what I say with a large grain of salt!😀

It's broken off, but you can still get at it with a pick tool or small screwdriver and switch the remaining bits over. I may just leave it just dont like having a broken part on it. Thanks again for the advice

Saying that actually, testing now and I can't get any midi input no matter where I put the switch, so it may in fact also be broken as I can see the bare contacts beneath from where it was in between the breaks of the switch.

A further update, although it was broken, once I opened up the unit I could see the contacts were still making contact. Blasted the inside of the switch with contact cleaner and moved it back and forth a few times. Its working! Thanks for advice!

Very nice! Maybe if you can't find a replacement maybe if your feeling adventurous you could disassemble and make a replacement for the broken plastic part. Not sure how much effort it would take but I have done similar things with scraps of ABS and some files.