Ok so I applied for a job recently. Sounded great, same pay packet, more freedom, less hours.

Had an interview today and obviously wowed them as they rang me up pretty much an hour after my interview and offered me the job.

-Here's the conundrum - the job advert said the job was 35hrs per week, usual stuff
-However at the job interview and in the job description they have, the job is 35 weeks per year pro-rata which takes nearly a 3rd of the pay (though 17 weeks off plus a further 5 weeks holiday i can handle)

Do I have a leg to stand on in making them extend it to a full year or do I have to tell them I am unable to take it? As I can't afford to lose that much money...