For the second part of the answer: you have fallen into the trap of thinking that every ticket goes for £50. In fact only a few go for that amount being the inflexible stay on Saturday night and return on the least convenient type. If you want to travel at a specific time there and back that does not coincide with this, then you will see your ticket price rise to normal BA levels.
Answer: BA should get rid of the last few empty seats by this cut-price marketing, and low-costs do not pay £5k for one sector unless it is really short.
Apols for writing whilst drunk on original (reason for his annoyance at me below)
[ 01 November 2001: Message edited by: Lucifer ]