Sorry should have stated that while I realise that the offer is probably a fairly decent one, there are more important considerations. I am not familiar with the system of offers in the English system but would assume that if you approached the college again in a year or so, they would listen to you (IF the desire to research is still there at that stage !!). The work experience will stand to you and may give you insights into areas you would wish to research.
If really stuck, let the flip of a coin decide - when you are just about to hand in your notice/turn down the Cambridge offer, you'll find out what you want to do. Sweet J€sus - I sound like an episode of "Dawson's Creek" now! Whatever you do, enjoy the weekend.