I had the fuel sensor on our Super Maramu replaced while I was in Greece. Wema built a custom unit for us out of the UK and sent it to us. The price was quite reasonable for a custom order ... however, yours ~may~ be available as an "in-stock" item so it would be less.
Check them at wema.co.uk and once you get that senor out of the tank you can measure it (as well as the screw-in size) and give them an email for a quote. They also will offer how many sensors you want for your assembly (we went with 12 ... I think).
At any rate, it was an easy replacement. I even wired in an on/off toggle so the sensor and gauge were not consuming power when not needed.