You can take the full amount of car from the bank and finance the first payment by giving them that big fat check you was about to give the dealer. The bank won't have a say on how much you give back on your finance monthly. But you will have to see if there will be any penalty for paying off the amount early when you ending your finance term. There is a promotion for $1500 cash back if you finance from dealer with 3.29%. I don't know if UK has this deal.
13 MR E92 -Akrapovic slip on, Varis, BBS E88, Mode Carbon Lip + Side Skirt, LUX H8, KW Clubsport, ESS Tune + ACM Test Pipes, OEM CF spoiler, OEM CF mirror cover