Around town, perhaps, but on a run you really could not tell. Time and time again I'm surprised how quick it is from 40/50mph up to 70/80 mph.
Yes, you can tell by a country mile. Its not that its slow - though the VAG 2.0TDi is a troubled lump for power, constrained by emissions issues, hence most use adblu, many have poor power outputs (to avoid adblu), and that's even with cheating the emissions

- its the power delivery. Even the flat torque of an Omega v6 is more exhilarating than sub 300bhp diesels, though not necessarily quicker.
I certainly ain't against diesels, and have had my fair share, but one thing they all lack is the excitement of a good petrol - to quote your good self, no drama when accelerating hard, even with the modern, overblown small engine variants. I fully accept Opti's views about diesel. And hell would freeze over before I next intend to drive within the M25, so I care not about rumours of bans/high fees, and I'm actually all for big city diesel bans. Clearly, that includes buses and diesel trains.
She wants an automatic, not manual.
I'm all for equality, unlike our Lincolnshire Doctor, but this is one instance where you really do need to put your foot down and give her a slap. If she needs an auto, go RWD. And a big engine. FWD autos don't work. Small engine autos don't work. And neither will give your current 3.2 much of a run for its money on MPG. FWD autos are compromised (and generally weak) due to space constraints, and small engines don't have the required grunt to make up for autobox loses around town.
To manage your expectations, the last small engined (1.6 petrol) auto I drove for any length of time averaged around 15mpg.
Added to that, both the naff Zafira and the even more naff S-Max are both heavy cars, most definitely unsuited to autos bolted onto their weak petrol engines.