Thank you for the information, Globaliser, dunk..very helpful. Spoke to BA on cancelling and upgrading or paying only through avios...the taxes are too steep and just dont make sense.

There is no option of a child seat in WT+ as well and I cannot buy a child seat for below 18 months ;-(.

My options seem to be limited to sticking with the economy now that the 24 hr period is over for cancellation.