My wife and I fly from Atlanta, Ga to London on 08/02/14, arriving at 12:15 on 08/03/14 on Delta Airlines. We will then fly directly to Dublin, Ireland on either the 14:05 or 17:25 flights on British Airways. Do we have to get our luggage in Heathrow and go through customs, then go to the British Airways ticket counter to check the luggage with them and then go back through security? I doubt Delta will check the bags through to a British Airways flight. We are currently booked on the 17:25 flight but would love to make the 14:05 flight but I have no idea how much time it would take to go through customs and then through the ticket line and then back through security. Can you help?
Yes, unfortunately you will need to retrieve your bags and re-check them. I haven't had this exact scenario, but I have flown on a mixed Delta/British Airways flight before, where customs didn't even play into it (Cape Town to Johannesburg on British, Johannesburg to Atlanta on Delta), and was forced to re-check my bags.
I don't know if any airlines have arrangements to transfer checked luggage like that, but British Airways and Delta (as of January 2014) certainly do not.