Hi Anthony B - thanks for your reply. I looked in the DCLG resi care guide but did not find much other than :
Page 94: - Means of escape – security
It is accepted that in many care home situations conflicts between the needs for means of escape and security may arise, particularly in premises which provide accommodation for people with mental illness, where it may be essential to maintain a high level of supervision during an evacuation.
In areas where security is important a properly designed and managed interface between staffing levels, installed fire safety measures and security measures should be sufficient to permit staff controlled evacuation systems. Any solution proposed, that includes security controls on escape routes, must be discussed and agreed with the relevant enforcing authorities, care provider and other relevant bodies.
However the DCLG GUIDE Healthcare Premises (does not apply to resi Homes) but P138 has a lot of useful info.
Based on this the green over rides are not a must.
Thanks