Thanks S.R.
I am starting to believe it is a new restriction and not sure whether it is route dependent or not - but certainly from Madrid 3EF are blocked everyday and I am not getting anywhere with releasing them, whether it is multiple supervisors in the call center or the chat function (they all blame the airport). And in your case, I do believe that given everything else was taken, they would have to release them to you, but that just highlights the arbitrary nature of this issue - not wanting to seat an 8 year old with their parent when there is space and it is in their purview to unblock and assign is somewhat ridiculous, especially in FC (and against their explicit policy).
Any ideas of who to contact? Pretty frustrated by this...
I don’t think it’s a new restriction. My partner and I are flying with our kids later this month. 3E and 3F were blocked. My partner called to unblock, and the call centre agent did so. This would have been last week. Suspect something else is going on, but can’t think what.