You might just about get into one from a non-franchise dealer, but be prepared to compromise on spec & be at the higher end of the mileage spectrum . Here are 2 of the cheapest on carzone:

http://www.driving.ie/used-cars/BMW/5-Series/BMW-520D/126914204572810420/

http://www.driving.ie/used-cars/BMW/5-Series/520D-SE**HI/107314171022614260/

Both are manual & I would consider auto a must on an F10/F11