There may be times when you do not have the full registration number of a motor vehicle of interest. This is where a site such as partialnumberplate can be useful, as it allows you to search partial UK & Irish vehicle registration numbers. If you replace any unknown / missing characters with a ?, then it will return a list of possible registration numbers for vehicles, along with the vehicles make & colour.
This is a free online resource if you are only missing a maximum of 2 characters, however there is a paid for service Here, if you are missing 3 characters.