The original prices for this event were clearly OTT as they were also for the Glasgow DL. I think someone at British Athletics has perhaps got carried away based on the Anniversary Games sales last year which was clearly partly based on the 2012 afterglow.
I think it was always going to be difficult to sell out 2 days of DL in Galsgow just 2 weeks before the Commonwealths. And the Anniversary Games should have been held in 1 longer session. I know they reduced tickets nearer the time for both but it clearly was too late and has probably irritated those who paid full whack too.
They will need to think carefully about prices & organisation when the Olympic Stadium is available again. There may well still be a 2012 affect initially but it will wear off sooner or later. I think at some point they may struggle to sell out 2 days for a DL. Maybe they should have a Friday night event on the Mall/Horse Guards (with prices either free or fairly cheap) followed by the saturday at the Olympic Stadium