Yes - BA used to have a day return and the overnight CPT-LHR would always fill up first. In particular most J and F passengers would prefer night flights (particularly on a flight that is that long!) The cost of parking a plane there for 8 hours where it is cheap to park is also not that much and certainly not like LHR where the cost is very high....

I prefer the double daily overnight each way and believe me for sure if it was not overall the best time to have the flights BA would not be doing it this way.....

FD.