Registration marks were first introduced in 1903 and they have since undergone several changes in format. However, they usually contain between one and three letters and up to four digits, with the digits following the letter combination or vice versa. Prior to the introduction of the suffix registration format in 1963, registration marks had no age identifying letters or numbers. It is therefore difficult to determine the age of a vehicle that carries one of these marks. Suffix registrations are age identifiable by their suffix letter. Similarly the prefix letter on a registration plate identifies the year of manufacture. New style registrations use the two-digit number to identify the age of the vehicle.

Suffix, prefix and new style registrations can only be assigned to vehicles of the same age or older. However, dateless registrations do not carry age identifying letters or digits and can therefore be assigned to any vehicle, irrespective of its age.

Dateless registration marks can be more difficult to come by, because they were issued prior to 1963 and the vehicles they were originally assigned to have often been scrapped. If you do obtain a dateless registration, it is likely it will be one of only a few similar registration marks on the road today. This means that they are often extremely sought after, even if they do not contain commonly used initials. Depending on the letters and digits involved, they can potentially be worth a lot of money.