Fire Brigade only involved with battery alarms for at risk groups in
UK.
Alarms with no battery back up must be taken back to separate spur on
consumer unit with no RCD.
Those with battery back up can be taken off adjacent lighting circuit;
this is recommended as if there is disruption on lighting circuit:

1/It will be readily apparent

2/It will get fixed

3/We have experience of tenants with alarms on dedicated spur
disconnecting circuit if alarm strats to nuisance alarm; they won't
disconnect a lighting one however!!

Follow this link for copy Installer Guide in pdf format
http://www.kiddefyrnetics.co.uk/ACSmokeHeatIM.rsf