Hello,
No it was an in principle question as I did not know how simple or not it is to add a car after the flight is booked and whether it is cheaper to add at the same time or in a few weeks time. I am an individual who uses BA about 12 times per year. Its 28th March LGW-LPA returning 11 April in CE, need the car at LPA airport.

I have tried Flight & Car from the front page if thats what you mean, and it is slightly more expensive than selecting the flight and then adding a car after. Any more tips for reducing the cost greatly appreciated.