The problem is fully documented in Vauxhall Technical Bulletin No.1979 and dealerships know about it. The dealerships were advised to change the radio under warranty and charge for the 20min job time. But ONLY if a customer complained enough about the flat battery. The dealership should not be offering to sell a battery or perform diagnostics when they *KNOW* what the problem is after being told by Vauxhall Motors!
All CD30 made by Blaupunkt from 2004 are faulty and the technical bulletin gives serial numbers. You just try getting it changed, dealerships are refusing but want to make more money by selling you a new one.
If you have such a radio, refer the dealer to the bulletin and take your radio card in for them to check the numbers.
There is NO fix for this radio despite what you see on ebay. The people offering to repair for 100 will later offer to sell you another one but it needs a TECH2 and is not guaranteed to work.