..do also bear in mind that the pm BOH-EDI is really rather late which might be putting off some people.
If you have to travel for business to EDI from the south the night before, you're unlikely to take such a late flight (assuming the purpose of travelling the prior day is to achieve an early start the next day)...similarly if you're on a day trip down from EDI, there is a long time to wait from the end of the business day until the flight goes.