I know you've already chosen, but thought I would chime in for future reference in case anyone else is looking at the thread.
I chose the opposite (1.4 COD vs. the 150ps Diesel) - having test driven both, I found the petrol more refined, just as quick (I've never been one to mistake the initial diesel rush of torque for overall speed, but can see how it appeals to many folk - just a personal preference one way or the other).
My main decider was, as a company car, the 1.4 COD worked out less expensive, both in the value of the car and also the monthly tax due to the lower emissions on the 1.4 s-tronic and the fuel type itself (in fact - the diesel was around £26 a month extra in tax with the same options on both vehicles - over the four years a saving of over £1200).
I also factored in the amount of miles I am likely to do - I don't do much over 12,000 a year and the trip to work and back is only around 5 miles each way - so fuel wise (my company does not pay for fuel) the Diesel would have cost even more over the 4 year period that I'll have the car for.
I guess if I had *really* preferred the extra torque then I may have considered the diesel a little more, but probably not - would rather have the extra money to spend on other toys