Can't advise on the choice of engine, but also take into consideration the insurance and routine maintenance costs - as well as have a test drive for of both versions for yourself, this might help you with your choice - also consider looking at the prices charged by brokers, such as advertised on this web site.

In general, the viewpoint these days is that if you do less than 15k miles a year, go petrol. BUT that's a generalisation. My mum, for example, only does about 9k a year. But almost all her driving is 50-60 mile journeys. So a modern diesel, with DPF, etc. is fine for her type of motoring.

At 12k a year, with lots of motorway use (you say 75%), I'd probably say diesel for you.

But you really need to test drive petrol and diesel versions, and see what you think. Myself, I like diesels. That wall of torque makes for a lovely relaxed driving style.

Is this the 1.6 Diesel engine fast approaching repeated turbo failure infamy?...of course they've fixed the problems, apparently, so those makers who use it are putting a 5 year unlimited mileage warranty on it? no thought not.

If you decide to go Diesel, i suggest you treat as a bad joke the makers service schedule which might give the impression up to 20k service intervals are suggested...pause for laughter....and change that oil and filter at least half the makers recommended interval...to cut costs you can DIY if you use genuine filters and say nothing to the dealer, but keep receipts as proof, it might help with a future private sale.

Thats not the question you asked, but it might be worth keeping in mind as you'll be out of warranty for 2 years, or more?

A search here and elsewhere about the 1.6 Diesel would be time well spent.

So, in case anyone is interested, I decided to put my order in for a new Fiesta Zetec 1.0T in Magnetic gray.

I figure the annual mileage will vary, and won't be enough to warrant the Diesel. Plus I enjoyed the 1.0 on a test drive with 3 adults in the car, it pulled brilliantly on the dual carriageway and will be perfectly adequate for my commute.

I ended up part exchanging my old Hyundai i10 and went a bit silly on the extras.

City pack, alarm, spare wheel, mud guards, boot liner, mats, scuff guards and the 5 year warranty.

I appreciate these aren't that exciting but they cover pretty much all my requirements :)

I'll update again, if anyone is interested, when I receive the car (6 weeks).

Cheers for the advice though! It did give me a lot to think about and after a few visits to the dealer it helped me narrow down what I wanted.