Hi if I was you I would take it to another garage, just for piece of mind.I understand that you trust your local garage, but I had a problem with mine when the warning lights came on the RAC came out put there diagnostic kit on to my car and could not clear the fault. So I took it into my garage where he put his diagnostic kit all faults showed up and he was able to clear them. I,m not saying this is the same fault but its worth a try depanding on the garage is how much they charge, the price does seem to be diffrent at garagesfor diagnostic report.