Another vote for Sytner
You can see the baseline deals on their site:
520d MSport Saloon -
http://www.sytner.co.uk/bmw/new-cars...t-finance.aspx
520d MSport Touring -
http://www.sytner.co.uk/bmw/new-cars...t-finance.aspx
530d MSport Saloon -
http://www.sytner.co.uk/bmw/new-cars...t-finance.aspx
Remember, these are just the starting points of your negotiations