how much does it cost to change a kitchen sink?

got a plastic one in at the moment, with matching mixer tap, but it's starting to stink

so we want to swap it with a normal stainless version, basin one side and the washer thing on the other and get rid of the current one which has that little bit int hemiddle with a smaller sink on the side with the drainer board ont he side of it

and new mixer tap

so, how much for the lot? bearing in mind we just want something that will get rid of the smell and do the job rather than having it all singing all dancing ( because i'm waiting for the extension to go in as my mate does granite for a good price, seeing as he owns the company )

london prices please, not outer hebridies ones that will cost me a sheep and some gravy thanks