Exactly the 1.4 ecotsi is 0-60 in 7.6 secs compared to the 9.9 in the diesel - the petrol has the same torque as the diesel too.
The petrol is whisper quiet as well - diesel not so much.
I'm happy to trade off fuel consumption against performance - depends what you want I guess.
I'd say economy is the primary driver, but when covering this many miles it also needs to be comfortable and perform well. The Mini Cooper D did 0-60 in 9.7, so in reality the TDI isn't much different.
No-one seems to own a 1.4 3 cylinder TDI 105 so it's hard to know how good the economy really is, and whether the difference is really significant enough to persuade us to go TDI over ACT!