hi there 

what is the acceptable way to  SURFACE  mount the cables between smoke detectors cos im thinking that twin and earth in a plastic mini trunking doesnt comply with the regulations that say fire supports need to be fire proof so im thinking you  may as well go the whole hog and use white fp200 with white p clips rather than messing around trying to trying to use some kind of metal clips inside a plastic mini trunking any thoughts ?

thanks alex 

Depends on how important aesthetics are to the client - if they aren't bothered then just surface mount with metal clips.