Have you got any tips for getting good economy out of it? I was going to PM you to ask but thought it would be beneficial for you to post it in the thread so more people can benefit from your advice.
I guess that was aimed at me
Most of the rules are the same as for any car - remember it's the brake pedal that costs you fuel (because it throws away momentum that must then be replaced) so you have to anticipate carefully to avoid braking (where possible). That means slowing for red traffic lights a long way back, in case they change to green. Keeping a distance from the car in front when moving slowly, so you don't have to keep stopping and starting. Lifting off early before you reach a 30mph zone, so you don't have to brake. As a bonus, passengers appreciate this sort of thing; it makes them feel they're in safe hands. No-one likes riding with someone who brakes suddenly.
Acceleration; use the engine in the revs range where it feels most smooth and powerful; say, 3000-4000 where the torque peak is, don't change to a high gear too early (a common mistake) - basically, you want to accelerate up to speed smoothly with half throttle, then change to a high gear only to maintain the speed on a tiny throttle opening. Remember that the fuel cuts off completely if you lift right off the throttle, so if you've got up to speed and can lift right off, that's the most economical.
In the 1.8 I'm guessing that 5th gear shouldn't be used for any sort of acceleration below 40mph; it will 'lug' the engine and you don't want that. Better to use a few more revs. It's not a diesel!
'Pressing on' to maintain a high speed - you know what I mean - costs you quite a bit more fuel than 70mph and for most journeys there is little time saving. Especially try to avoid maintaining a high speed up a hill - it's worth building up a bit more speed on the downhill and letting the speed tail off going uphill so the engine is not having to work as hard, but try not to annoy other drivers in the process, of course.
Incidentally I found the most annoying drivers in England were the ones that speeded up and slowed down at random (not like I just said, but all the time), dithered at road junctions, didn't indicate, etc. People doing a steady 60mph on the motorway weren't really all that annoying because you have three lanes, I just blasted by at 90mph in my three-cylinder rented Corsa.
Maintain momentum through the corners by careful, smooth high-speed cornering - this is where you get back the fun factor
So basically, it's not about driving slowly - it's more about conserving the momentum you have by not braking unnecessarily, and it's about using the engine efficiently - get up to speed and then just maintain it on a tiny throttle opening - avoid the temptation for full-throttle standing starts, etc. which you rarely 'need' anyway. But at the same time, you don't have to crawl away from the traffic lights; better to (again) get up to speed smoothly, then maintain. I can't emphasise that enough
Vehicle-wise, make sure the engine is properly timed (variator/cam timing spot-on), good sparkplugs, tyres correctly inflated and wheel alignment correct.
You probably know all those things anyway but that's it - last night I averaged 7.0L/100km over a 340km mix of motorway and city driving, which is about half the fuel that my friend's BMW 325 uses for the same trip. I'm happy with my Twinspark