The TA is fun to drive. I know I would find it very difficut to rein it in all the time, it's just too easy to shoot away at the lights, so I would never get anywhere close to the quoted figures.
In fact, I believe that drivers who don't really enjoy driving waould be better off with the 1200. Horses for coures as always.
As for Diesels, they are intrinsically more economical and seem to give far closer to the quoted figures. My ten year old 1.9 JTD gives practically identical figures to those quoted, and offers 46mpg at a stedy 80-90, which I reckon is good. But the Doblo has a CX figure of 31, which is good by any standards. The reason: flat sides, a reasonably flat undercarriage and a cam tail -a big flat tailgate in other words.
I do drive rather quickly though, and hate pottering about anywhere. I think cars like this too, as long as they aren't flogged when they are cold