First question, why have you chosen Accounting and Economics at Southampton as opposed to their Economics and Finance course?
I think firstly you need to decide on which programme you'd rather do. They are both going to be very different, with one having a strong focus on accounting and management, and the other on finance. In fact, I'd argue Southampton's course is more Accounting and Management with Economics as opposed to being Accounting and Economics since only a quarter of your modules are taught within the Economics Division.
If you have taken A-Level Maths, then at Southampton you can switch after first year (or during first year) to the Economics and Finance programme. This is a rather good programme and I've a lot of friends doing it. Their only complaint, however, is how mathematical it is.
If in your position, based on the programmes alone, I'd opt for Surrey as firm and then I'd be undecided on the insurance choice.
Also, as a note, don't be so hung up on the whole industrial placement thing. A lot of universities are advertising these and pushing them as the panacea given our current economic climate. They're not. You'll do equally well in the job market if you get an internship each summer while at university and also try for during the Easter holidays too. This will put you in as good a position as someone who only has a one year long placement.