Thanks for all your input. I am just waiting for the finance to be OK'd and I am going to go ahead with it I think. I went to price a used BMW up and they wanted 12.9%!
I am currently working away so the thought of the wife having a brand new car with warranty is really reassuring. I have put 10k miles but rarely do more than 5k a year. Will see how it goes, I have only ever had one new car before albeit an Aygo (I did eventually fall in love with it) so will be counting down the days until its delivered!