So, what for the future? The next obvious goal is 5.0 L/100km (47 US mpg).
I think this is going to take more than careful driving and pumped-up tyres, so ... It's time for some more mods.
As a starting point, I've just fitted an injector kill switch.
Using the ignition key also turned off the speedo.
Because the engine sometimes restarted if I made the key-off time too short, I often missed out on recording 50 or 60 meters every time I used EOC.
Given that I use 25 or 30 short EOCs going to work, that adds up fairly quickly.
I'm off work for a few weeks now, so I'll have to wait to see how much difference this might make for a normal commute.