Physical Security
Top Crime Reduction Tips for Retail Businesses 
Standards & Testing - Doors & Locks
Physical Security - General Advice
Use the National Security Inspectorate (NSI) website to find companies they have approved in your area
The NSI is an independent, not-for-profit approvals body that inspects companies providing home security, business security and fire protection services.Choosing an NSI approved company ensures that the contractor you select works to the highest recognized industry standards as demanded by the police, fire services and insurance industry. http://www.nsi.org.uk/
Use SSAIB’s website to find companies they have approved in your area.
SSAIB is a specialist Certification Body for providers of electronic security systems, fire detection and alarm systems and guarding security services. Their aim it to promote high standards within these sectors and to provide recognition for those who achieve them. SSAIB is a Security Industry Approved assessment body specializing in the Security Industry. http://www.ssaib.org/Home.htm
BSI British Standards is the National Standards Body of the UK. You can use the security standards section of their website which lists and explains all the various standards http://www.bsi-global.com/