Peter , we stopped giving out advise some time ago , we found our own trade the worst , we would give them free technical advise usually common faults then later we would learn that they had tried changing the parts that we had mentioned and not surprisingly it didn't cure there fault and then we were getting a bad reputation for miss diagnosing there fault even though we had not set eyes on there car . Company policy know book in the car so we can diagnose the fault (we test not guess) we are also trying to avoid any while you wait diagnostics it uaually causes problems with the usually comment being it only took ten minuets how can it cost that much .