Some very basic points of law, needed to be be met for evidential reasons acceptable to a court.
Was the pressure gauge HOME OFFICE certified with an up to date certificate, has the policeman got the necessary qualifications to use that piece of equipment, these are questions which will quickly get the case chucked/charge dropped.
Personally I think ROD gives them more credit that is due, yes there are some ace plod, but there are a fair number of jumped up wannabes looking for easy hits, who forget the set of rules/LAW can work against them also if they make up their own.
Speaking as a "young un" of 45 years who just conducted his own defence case of dangerous driving against norfolk plod, who even had VIDEO evidence and either 11 or 13(I forget) police witnesses, and managed to get the case chucked out in CROWN COURT in less than 15 minutes, wasting around £60K in 11 months they had to prepare the case VERY badly.
tabetha