Well got tired of the rear brakes squealing so I thought I would give these a go and they seem to have worked.
1/2 a days work. I found out my 15mm spanner would not fit so machined that down and then the caliper came off. Brake pads out and then cleaned up shim stuck on and all back together. The first side took me two hours but the second side once I knew the process took only 30 mins.
Mine were about £8 from Ebay so not bad quick fix really.
[ebay]250665386402[/ebay]
So 3M shims get the thumbs up!