You're a rare breed for a UK street bike owner. All the UK ZX-9R owners I've known over the years show a clear distaste towards anything but ragging the tattas off the bike, as they claim. In fact, the fewer miles they get to a tank is almost a matter of bragging rights, as if to show how badass they are on the bike's throttle.
While the 899cc ZX-9R cannot match the NC750X on MPG, the EVAP version is a performer that surprises.
BTW, do you recall if you were filling with E5 or E10 and/or are you monitoring which fuel types result in each of your log results? Would be good for before and after the September 1 introduction of E10 there.