I have a few similar questions related to this.

We are looking at booking a 2-for-1 redemption for myself, wife and 1 year old son. He would turn two before the inbound leg.

Taken from https://www.britishairways.com/en-gb...avel-documents - "If you're travelling with an infant who reaches the age of 2 during their journey, your child will need their own seat for any flights on and after their 2nd birthday. We won’t charge you extra for this; you'll only pay the infant fare for the entire journey." it's clear this is possible.

But I have the following two questions if anyone has experience of the below.

1. Does this apply for BA codeshare flights or only BA operated?
2. Can we pay for a seat for my son on the outbound flight (either Avios or Cash) if desired but retaining the free return seat?