I keep getting flat battery prob every few days or so , the car has had a new battery  and alternator . At first i thought it was the fact that i had upgraded the stereo to a ford/sony dab unit , so i fitted the old cd6000 back in only to find this morning it is flat again .I did not unplug the bluetooth module i left that alone , my question is can a bluetooth module drain a car battery that fast ? thanks for your help

You can't just guess at it being the Bluetooth module, it could be any number of electrical components causing it.

You need to do a parasitic draw test by following this procedure.

Get a multimeter, remove the negative terminal and put one lead on the battery terminal and the other lead on the negative cable. Set your multimeter to amps and check how much current you have being drawn by the car. My guess is you'll have a draw above 200mA if your battery keeps going flat.

Start removing fuses 1 by 1 till the current drops off, then you've identified the circuit at fault. Once you've identified the circuit you can narrow down the potential components at fault and rule them out one at a time.

When you do the test, make sure the doors are locked, all lights etc. are switched off and you've left the car for half an hour ish. You'll get a false reading if you don't, as some of the modules will be awake and drawing current.

Unless you do this test you're just guessing as to what's at fault.