with tune ecu you can just turn of the O2 sensor so the ecu does not lean out the bike in the narrow ban width area the sensor controls. Power commander makes a plug that fools the ecu also. But like I said you can do this stuff via software. Along with many other things. Yes there are a buck load of tunes and some for other countries where power restrictions apply. (not that some of those people do not correct the power loss) What really matter is what your MOT inspector thinks
If you have to get that done!!!!! Good thing is you have plenty og Blokes across the ponds that know their way around MOT stuff