Yesterday I booked one way (won't return back) ticket for my family including 2 adults and 2 children ( 5 years & 2 years) using my accumulated avios. I booked for may 3rd because none of the other dates in May and June no inventory available for Avios booking. This date is took early for my planning but the customer rep of BA told me that you book online first and then keep monitoring the avios seat availability for the dates that I prefer (mostly from May last week to Jun 1st week). As I said before BA website tests our patience hence any web site or email alert would be helpful for my change of itinerary.