Late reply!
Thanks for the welcome
I still have the Auto Bluebird. I've managed to increase my efficiency from 28MPG to 32MPG (I think..) - will need to wait till I fill up next time. It is hard work with the auto box though.
I'm about to start (in the next few weeks) on an extreme eco modding drive... The first thing is to look at NZ laws regarding modifications - I think I can get away with unlimited cosmetic changes. I don't think I can do a basjoos boat tail, as the overhang would require a special re-inspection which I can't be bothered to do (yet), but I'm thinking of (probably in this order) : rear wheel skirts, including rear mud-flap aero extensions, moon discs if I can get some, tyre air deflectors (and teardrops behind them!), undertray, modify front bumper so more air flows over the car, rear boat-tail (pretty extreme but not a basjoos teardrop one), front wheel skirts (might be impossible to do, but even if I do a small partial one, it should help).
The idea of a manual transmission is becoming more tempting too. I'm v. tempted to get all the parts I need, keep them over winter, then when the weather becomes good again, either fit it myself or take it to a garage, while using my e-bike to commute to / from work!