Despite Mrs Clam having aisle and I having window set as our prefered seating, invariably travelling together, traveling CE or CW, the system on at least 60% of occasions will assign us seats which are the complete opposite. Not an issue as we simply swap ourselves but still somewhat baffling. Glad of now being able to select seats free at time of booking but if we ever forget to do it straight away i've no doubt the system would decide to put the good lady next to the window and myself by the aisle.