doelectrics

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