I would wait and see what they offer for sure before making any definite decisions on this. Having a two year old in the booking may work in your favor and have certainly seen BA re booking people with flybe in the past. However, as the international leg is operating and there are suitable (albeit totally inconvenient) alternatives for the domestic connection up to GLA on their own stock, I wouldn't hold out too much hope of the option you're wanting.

That said, silver status and travelling with a 2yo may help. Keep trying on the telephone and give it your best shot in persuading them. Good luck!!!