Beagle you are entirely correct regarding the miscounted engines by the BA bean counters, I was the single POC for the initial operation using BA crews and this story was related to me by a number of BA personnel. Also, very soon after selling these aircraft to the RAF BA were leasing back Tristars from Air Lanka to fill a gap on the South America routes. Of interest the original BA 500's were 'returned' to Lockheed to be uprated as they failed to meet the advertised payload/range which I believe was based on a London - Vancouver direct sector and as a result were at the time significantly more capable than any other L1011s.