From CRB website:
Standard checks can be applied for by people entering certain professions, such as members of the legal and accountancy professions and applying for specified licences. A Standard check contains:
An Enhanced Disclosure is available to anyone who works in what is known as a “prescribed position “. These are the positions which are in the ROA and have also been named in Police Act Regulations. Regulated Activity with either Children or Vulnerable Adults,certain Judicial Appointments and Gambling Licence Applications are examples of prescribed positions.