The Avensis has indicated 48 mpg, and as £15 covered 170 miles and put the fuel gauge back where it started, it's probably about right. No idea of the road tax for it. It is very long, harder to park than the CRV, but a pleasure to drive. After the brief freedom of an auto though, I really am ready for that CVT...! My last doubt over the efficiency of the auto is put to rest be people confirming the CVT transmission in a hybrid is actually more economical than a manual.
Not bad for a big family car I guess, I'm sure you could get mid 50's if you tried. Toyota know what they're doing, the gearbox in the Prius is optimised for such a car to give the perfect balance between performance and economy. As much as I prefer a manual, look at other manual hybrids, such as the CRX and the old Civic, thier economy is pretty poor about 45 MPG overall.