Thanks for the reply
@cel_disney
When we booked the trip, it wasn't an issue as (as far as we knew) we were getting DME from airport to Resort, then DME back to airport where we would pick up a
Royal Caribbean coach transfer to Port Canaveral. However, we were then informed that as we are the only family doing this, our TA has arranged a direct transfer by minivan from Resort to Port Canaveral (which is obviously better), except that it has thrown up the child seat issue which would never have occurred to us.