In the UK, licence plates are assigned to a particular vehicle when it is first registered (when it is delivered to a dealership as new). The plates currently go in the pattern LL62 LLL, where the L is a letter and 62 denotes it was registered between 1 September 2012 and 29 February 2013. There are two registration changes a year, on 1st March and 1st September, and for vehicles registered between 1 March 2013 and 31 August 2013 the pattern will be LL13 LLL. For vehicles registered after 1 September 2013 but before 28 February 2014 they will have the number 63, from 1st March 2014 to 31 August 2014 will be 14 and from 1 September 2014 they will be 64 and so on. This system began in 2001, prior to that it was a different system but it is still possible to tell the age of the car from the plate. The exception to this is people can buy 'vanity' or 'cherished' plates, which may have a different year indicator (though it's illegal to make a car seem newer than it is with a vanity plate) or none at all. The registration document and the vehicle's history as kept by the DVLA will show the original plate as well as the chassis number.
Insurance policies are sold by insurance companies, and are almost always in the name of the registered keeper (the person or corporation whose name appears on the registration document, the v5). The policy will vary in price depending on the type of vehicle, the use the person is going to make of the vehicle, the driving history of the person and any other drivers including points and accidents, and whereabouts in the country the main driver lives. The insurance policy generally lasts a year but most people pay for them month by month so a failed payment may mean that the policy is no longer in force, although the insurer does have to follow some steps before they void the policy.
All these insurance policies are kept on a database to which the police have access. Anyone who owns a car can check the insurance for free on
ASKMID; non-owners can check on a vehicle for £4.
Many police cars are fitted with ANPR (automated number plate recognition), so uninsured vehicles ping up a warning and can be stopped. The police can also check, if someone is stopped for another reason, whether that person is insured to drive.
Mechanics, detailers etc who would need to drive a customer's car for a short while would be covered by a blanket policy taken out by the owner of the garage, this will provide them with insurance as long as they are driving the car in connection with their employer's business. Mostly, the mechanic's driving history, points etc wouldn't be checked but the blanket policy might specify no driver under 25, or no driver with more than 6 points (for example)
Company cars are mostly insured similarly under a fleet policy, but in the case of fleet insurance the person who will be driving the car may have to declare their driving history in terms of points and accidents.
Every vehicle has to display a 'tax disc'. These last for either six months or a year, vary in cost from nothing to £lots depending on the year of first registration (if that date is prior to 01/01/1973 the car is exempt), whether the driver is severely disabled (exempt) and the amount of emissions from the car. The more polluting the car, the higher the tax disc. The discs are different colours every year so it's easy to spot an expired one at a glance. In order to get a tax disc, you have to have insurance and (for cars over three years old) a current valid MOT certificate. Even if the vehicle is exempt from paying for a tax disc, you still have to display one, it just costs nothing.
The MOT is a test done to ensure that the car is roadworthy, once a year on all cars three years old or older. MOT certificates are also on a database, so it's not always necessary to present all the documents at a post office to get a tax disc, you can get a new disc online.
That's not completely comprehensive but it gives an outline of how motoring law wrt to insurance, number plates and tax discs works here. Any questions, just ask.
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