Invites could still easily be going out into the back end of next week I think. Someone on this forum received their invite yesterday (or Monday perhaps?) who had applied on the first day of the window.
Either progress is slow or BA are spitting successful applications out in a non-chronological order back to the FTOs for their consideration. It is reasonable to assume either case.
Either way I'm still waiting and doing my best to be as patient as possible.