Most personalised number plate brokers will value number plates on behalf of clients. Select offer a free number plate valuation service on-line, in order to receive a free valuation you must fill out a short and easy form on the website and one of the valuation team will send you an email back with a value of what the number plate is worth at that present time.
A number plate certificate can also be purchased at a cost of £14,95 from select (Cost may vary with different brokers). The plate will again be valued at what is it worth at the present time in the market. Bare in mind private number plates can vary in value depending on the climate. Most personalised and private number plates do go up in value over time.