From where I am, on the other side of Bevendean valley, couldn't see exactly what was alight but it could be Bevendean Farm, which might explain why a fire engine came right up Lower Bevendean only to find it was some distance away and at the bottom of the hill! Fire engine eventually turned around and presumably reached fire via Warren Road.
I hope your right ( not in a bad way and everyone is ok ). Recieved a call advising it was the racing stables and had a panic. Fire engine went into Bevendean but were miles away, sounds like it ties in with what you report.