I did a search on the CAB website www.adviceguide.org.uk which brought up a useful link for the NACRO website www.resettlement.info that took me to a section on CRB disclosures, in particular spent convictions, rehabilitation periods, and occupations where you have to declare convictions (working with vulnerable adults or children, professions such as health, law, where national security may be at risk and some jobs within banking and financial services). Don't know if this is the type of thing you're after, but it's a start!