I wouldn't assume that is the case any more than I would assume that all firearms officers are a good shot. Some of the former specialist vehicle examiners in the force here were trained by UK police to the UK qualified standard and I can tell you that in some cases they didn't know their posterior from their elbow on some matters, but nevertheless they presumably passed the exams!
I agree with the observation that whether the calipers were different sizes and whether they affected the braking adversely are two different things. They clearly shouldn't have been, but whether they contributed to the accident MAY have been a different thing entirely.
J@mes I think you have got the wrong end of the stick about "censorship", the forum moderators are keen to ensure it does not degenerate into a slanging match especially given the fact that Gresh is known to a great many forum members. That is all.