I think there might be some confusion here (or is it I am confused).

If you book a proper tour package holiday (flights, accommodation, car hire etc using them as traditional travel agent) through one of their brochures its eight weeks before you go.

However, if you book through the BA Holidays website portal and do the items individually then you do need to pay there any then. Think BA need to change this though - I will never book car hire, hotel without the ability to cancel.