Yes I know. So they are currently offering to do it "again" for free to regain my trust (yeah, like that's going to happen!), but "favouring" me by doing so as they are claiming that it was done. I haven't coverered all avenues yet, but if I do end up doing it myself, I will (probably) be able to ascertain that it was or wasn't done. If it looks like it was done I'll go and apologise (cos that's the kind of guy I am

). If it looks like it wasn't I'll take a sample down to the garage stick it under the service managers nose and tell him what I think of him