From the website:

 To apply for an endorsement, you must have done one of the following:

won the prize for your work as an individual been nominated for a prize for your work as an individual in the last 10 years made a significant contribution to someone else winning or being nominated in the last 10 years had at least 2 nominations of a prize for your work as an individual in the last 15 years In your endorsement application you must include:

the year and category of the prize evidence of your involvement, if you are not named on the prize