You know it was wrong and we knew you know it is wrong. You asked for FACTS about odometers and my first post clearly stated that they are not required by law to be fitted to a vehicle. They are not tested and the only time any legal action can be taken is if you sell it claiming the reading is correct when it is known not to be. Read through the Road Vehicles (Construction & Use) Regulations 1986, I once was required to know most of it inside-out, and you'll see it is not covered.
However, although Cons & Use is still the foundation of our laws we have had many issued by the EU over the years that may or may not be in effect here. Regulation No 39 of the Economic Commission for Europe of the United Nations (UN/ECE) — Uniform provisions concerning the approval of vehicles with regard to the speedometer and odometer equipment including its installation [2018/1857]
‘Odometer’ means that part of the odometer equipment which indicates to the driver the total distance recorded by the vehicle since its entry into service.
2.6.1. ‘Technical constant of the odometer’ means the relationship between the input revolutions or pulses and the distance travelled by the vehicle.
5.5. The display of the odometer shall be visible or accessible to the driver. The odometer shall display at least an integer number composed of a minimum of 6 numerals for the vehicles of categories M and N, and at least an integer number composed of a minimum of 5 numerals for the vehicles of category L (*Moped). Nevertheless, the Type Approval Authorities may also accept an integer number composed of at least 5 numerals for the vehicles of categories M and N if the intended use of the vehicle justifies it.
5.5.1. In the case of vehicles manufactured for sale in any country where imperial units are used, the odometer shall be marked in miles.
8. PENALTIES FOR NON-CONFORMITY OF PRODUCTION
8.1. The approval granted for a vehicle type pursuant to this Regulation may be withdrawn if the requirement laid down in paragraph 7.1 above is not met or if the vehicles have failed to pass the checks prescribed in paragraph 7 above.
8.2. If a Party to the Agreement which applies this Regulation withdraws an approval it has previously granted, it shall forthwith so notify the other Contracting Parties applying this Regulation, by means of a communication form conforming to the model in Annex 1 to this Regulation.
All this defines what an odometer should look like but does not say it must be accurate or give a course of action if it is not. Under sec 7 it only requires the speedometer to be tested and corrected if found wrong. No mention that the odometer should be tested and corrected.
I believe your next step lies with consumer laws like the Consumer Rights Act 2015. Supply of faulty goods that you would expect to be working. If the suppler is not playing ball you need to think is it worth taking legal action.
Non Mog stuff