This is because DVSA's online registration will no longer accept your application or renewal without this information.
Make sure you have a valid certificate
The certificate must be no more than 6 months old, provided by DVSA's contractor, GB Group, and be specifically for DVSA purposes.
The online registration system won't accept a certificate that has been provided by another contractor or has been produced for another role.
Don't leave it until the last minute
You should apply for your DBS certificate in good time as some police forces may take up to 4 months to finish their checks.
DVSA's registration team will continue to send out reminders 6 months before ADIs' registrations expire. To avoid any delay, please make sure that DVSA has your current postal address.