The 11am departure would be 'brunch' which doesn't seem to be well liked.

I guess you have to decide what you could use the miles on otherwise and make a call from there. If it's a special trip, I would be tempted to do it, although the lounge offering in the morning is a bit scant, too.

Note that on BA holiday bookings, you don't get the proactive online upgrade options in advance, but they may be on offer on the day.