mines fixed.it was the heater core(inside the matrix). cost me 150quid from bmw , and labour was actually 300quid at an indy and the dash is perfect lol.
i would advise you re check evrything on your car.
1)put your heaters on with the car off.low setting fan.then change the temp from full high to full low and low to high and LISTEN by the middle vents to hear the blend doors electric humming.change from full hot to full cold on both sides quickly.if they are humming they should be working. park somewhere quiet.
2)see if you have even a small amount of heat.put it on cold, full cold, then adjust both sides to full hot and see if it changes abit.even abit means they are working.i had heat on level 1 fan.i had heat for 30 secs on full. i had on 1 side only sometimes too!
3) heater core...my pipes were very funny.sometimes they were both hot indicating water is flowing through the core but it can still have a partial blockage.. my best advice would be just get the core done. thier isnt much else that can be wrong.
dont listen to silly advice about water pumps,...thermostats and fuses and sensors. or anything else.electric faults normally show up.
flap motors can apparantly be physically checked just by removing the vents!? not sure. and if you are gonna pay for the dash removal they might aswell check/change the core.
just bite the bullet mate.