Sharp commercial microwave R21AT

[Turnip]

Hi folks,
Have one in where cust says that pressing the control panel often gets no action. Other times the microwave fires up by itself.

Notice it's a membrane control panel, listed as 3-2-1 in the service manual. Where to find one though as no-one seems to stock them - Sharp themselves refer to service centres - Not so useful for me though to make the repair pound, and although the machine is pretty basic in facilities, it's also rather expensive - Chris.

Forgot mention part number - FUNTKA899WRE0