Which diesel would suit me?

[srob]

Hi, I'm in the process of a serious 'belt tightening' excercise, and with the rising fuel costs I'm going to have to get a more economical car.

I've had a look around, and being a bit of a Citroen fan I've decided on a C3 diesel.

I'm trying to decide whether to go for the 1.4L or 1.6 though. I currently do 27 miles each way to work, 20 of which are NSL dual carriageway. Would a 1.4 be any more economical when 'keeping up' with traffic on a pretty deserted dual carriageway? The other thing I need to take into account is that I'd like to be able to tow a trailer with two (fairly light) motorcycles on. It wouldn't be a regular tow car, just if (/when ) a bike dies. The 1.6 seems to be slightly more thirsty and cost a bit more to tax per year, but I suspect it would make a happier tow car and I reckon in real world driving, on the trips I do to work it wouldn't be that much thirstier.

Anyone have any experience of either cars, and any real mpg figures to help me decide?

Dull subject I know, but any help would be greatly appreciated, this will be my first foray into diesel ownership!