Werkes Exhaust on UK bike ?

There are O2 emulators out there that might work. For a post-cat sensor, you just need one that has the correct resistance. You should be able to read that value with an OBD scanner.
I suspect that may be easier said than done. If the ECU senses the second sensor is not recording the emissions within the range it's expecting - it won't start
 
Didn't Jethro Bodine of the Beverly Hillbillies convert their model A to run on water instead of gas?

I need to watch that episode again.