Thanks for all the comments so far, I may be completely missing the point here so forgive me if so, but one of the main reasons for me wanting a 'newish' car was due to advances in technology making it far easier to get more miles to the gallon. What I probably haven't thought about deeply enough as you have said is the depreciation outweighing any kind of saving this is likely to give me.
Similarly with the 3 year dealership warranty. I liked the fact I was covered, whereas if I spent say circa £7k on a private sale car, this risk is higher.
My last car for example, my E39 was costing me an absolute fortune and only did 30mpg if I was lucky. Fuel alone was costing me £200 a month, insurance £117 and tax (if worked out monthly) around £20. That's £337 per month, just to run it.
I guess I looked at this Fiesta and thought "£70 per month insurance, £247 per month loan repayment and £100 per month fuel, so in total £417 per month all in". That's only £80 per month more than I was paying previously, and instantly I've gone from a 15 year old 30mpg car to a 2012 70mpg car, and on top of this, it'll be worth more than the E39 ever will when I come to trade it in.
At this point, I know exactly what you're going to say and I'd assume it revolves around quality and the type of vehicles we're talking about here. I totally agree - the last thing I want is to 'downgrade' (no offence to anyone with a fiesta) from a BMW to a Fiesta, however I just could not justify the running costs, coupled with the fact that at 15 years old now it's starting to slowly deteriorate. I felt like I was piling money into it constantly.
Fuel savings alone would save me £1515 per year, again... this is in favour of the fiesta.
The APR on the loan is 9% as opposed to 15% odd for car finance.
The above is my initial thought process, albeit completely irrelevant now as I don't plan on buying the Zetec S after seeing it, but similar applies to other cars.
Do you honestly think I should pay the loan back, save up, maybe buy a banger, and put money aside for a house deposit?
I'm 20 years old, and whilst you're right, at the minute I have no savings (I'm sure you'll appreciate it's extremely extremely difficult at the minute) I may have been (had I of not posted on here) tempted into an impulse buy that I would have lived to regret. Forgive my ignorance on the matter and lack of life experience, but I came here for advice and appreciate the responses given. I dare say a fair few people on here are a lot older and wiser than me, so any advice/suggestions are appreciated