I have met the senior manager from NA this morning and we had a lengthy discussion about the outstanding issues.

I'm happy to say that the tyre that had the blow out was not replaced by NA, even though the location on the invoice was driver side rear.

The manager explained that he had checked the make and model of the tyre and it did not match and I am happy with his is assessment.

We do not know how the tyres became mixed up, but because the car was in their garage so many times it is highly possible that it got swapped during one of the visists.

Although he gave a gaurantee about all of the tyres on the car, because of the nature of the blow out, it appears that it is due to a manufacturer defect.

I also explained that I had not yet replied to the letter from CEO because I was still not 100% confident that the car was driving as it was before this started.

We agreed that I would take the car to another garage to get a replacement tyre and would let them asses this outstanding issue.

If they are happy that the car is ok then I will write back to NA and confirm that the problems with the car are now resolved.

The only thing left to do at that point will be for the CEO to convince me that they really have overhauled their QA process like I have been advised.

I have also agreed with NA that I will update this thread with the outcome no matter what, so that it least we can get closure on this.