My DSC light came on and I took my E90 320d to the dealers to have it diagnosed. My car had 68k miles with FBMWSH so I was expecting this to be covered by a goodwill guesture. But no, I was told that my DSC hydraulic unit needed replacing and BMW would only pay 50% of the part.
I called a local place who have the same diagnostic stuff as BMW. The guy came to me and plugged it in. He said that he can do for £400, using original BMW parts. I snapped him up. He came the next day and took about 3 hours and hey presto! all done light is off and the new unit has 12 months warranty.
If anyone needs his number then just pm me. Really good guy - definitley recommended. He is in Luton.