Re Kitemark can't work
1. As happened with electrical products there was a period of grace, 2 years to get your kit in order, the UK even got an extension for a couple of extra years. Which means that new code released after a certain date has to comply. Code released prior to the implementation date did not have to comply. Change your old code/product then it has to be tested.
2. Same argument was used for electrical products. Didn't work. If fred in his shed has real faith in his product, he will invest or get investment in his product. EMC certification can cost between £500 to £Thousands to test, but you can use self certification, but you must have documentary evidence of your tests, a technical construction file. If your product is caught out, you must defend it or withdraw your product from the market place.
3.A rating system, even the kite mark being denied for free software.
4. If you have a standard to comply with, your money and time are better spent on that.
5. ISO9000 parts 1 & 2 show you have traceability of your parts and processes, good, but it does not stop you putting out crap products, but the software is wonderfully documented. There is already the TickIT scheme for software development.
6. Policing? As with the EMC standards, Trading standards police it now. And of course it has not been unknown for competitors to test the other blokes product to see if it really complies. The Germans were very good at this, test the other companies product, if it fails, its withdrawn from sale or loses its certification.
7. It does not have to be the "Kitemark" so many products these days have to comply with a whole raft of EN standards. Before I start a product design, I first investigate all the safety and EMC standards I the product must comply with. There are many, and if I don't the customer does not get his CE mark. Added to that, the product must comply with the RoHS directive and the WEEE directive, if its automotive then add in theELV directive.