I appreciate your comments KingCanute and explanation. Thank you very much for taking the time to comment.
However, and this is just my opinion, if someone if not an experienced long distance traveller, booking flights on line for a family of six travelling together, there was nothing on screen when going through the booking process that listed the alphabetic categories you mention above, and it was only post booking when receiving the itinerary that alphabet category was noticed.
As with all things we are now wiser after the event, but I dont doubt we will not be the last family to make such a hiccup and have a 10 hour layover before their next flight. Hey ho, I am sure we will cope but personally, I just think it should be a little more transparent on the website.
Many thanks though.