to be honest, NOTHING on that list you have put on your very first post is anything you would notice or even know about, let alone try to cover up ... Looking at the dates you have put up, anything could have happened to that car in a month, parts wear out, how can you be expected to take responsibility for a valve shim or a lambda probe?? The guy might have been driving everywhere at 8000RPM, or have filled the car with a fuel that would kill the probe....

Sorry, I would tell him to do one on all counts, he was happy when he drove it, happy when he bought it. Fair enough if it had gone wrong immediatly, but everything on your list is a consumable item, no one knows how long they will last, or how the guy has treated the car. By going to somwhere different first and not even contacting you, I think he's just trying it on ....

I get accused of having a go at traders on here , but only when they deserve it, fair is fair IMHO- treat people well and they will treat you well. As far as I can see you have done everything by the book, and having seen the times you have gone over what is expected to help people out after-sales, I think you have every right to tell the guy to do one, stick to your guns