We just returned from two weeks in Ireland. Great trip - driving following the Rick Steves route. But, the Heathrow experience was a real problem. We have avoided Heathrow for 10 out of 11 previous trips to Europe. Usually flew non stop SeaTac to Schipol. No non stop available from SeaTac to Ireland, so we went British Airways through Heathrow to Dublin. We thought it might be OK because it was all in the same terminal - Terminal 5. But NOOOOOO.....
We had 2 hours between flights both coming and going. NOT ENOUGH TIME!!! We have no complaints of British Air. My main complaint is the Heathrow employees who direct the lines for security and customs. Don't always believe them when they direct you to those long lines! If you do, you may miss your connection. They were wrong both coming and going. Be alert and assertive and ask the most knowledgeable looking Heathrow person which line should you be in. If you have to, go up to the security checker and explain that you have a flight in 30 minutes and ask if you can move up.
We had a super long line half hour experience in customs that left us little time to make our connection. So, I asked/begged the security checker and he let us skip another half hour long wait in the security line and go right hrough. At first he said no, you have a half hour, you will "probably" make it. I said no, I don't think we will. He finally relented and let us come right through. We did make it, but with just a few minutes to spare because there were several other hoops we had to go through after that security including being told we had go up 5 levels, go out of the terminal and come back in and go through security again.
Then on the way back, our plane in Dublin was delayed an hour to change a tire. So we landed in Heathrow with one hour before our flight to SeaTac. Half the plane had timely connections to make so British Air was as helpful as they could be.. But again, it was the Heathrow workers who made it near impossible. They again directed us to the wrong line which was a LONG security line. Luckily I overheard a knowledgeable looking guy in the distance say "international flight" to one of our fellow passengers. I waived my boarding pass and yelled - "we are going to Sea Tac - that is international - shouldn't we be going to that line?" He yelled back "YES, GO!! Get your husband (who was in the long line) and GO!" I looked at the guy who told us the wrong info and he still insisted we needed to be in the wrong LONG line. We ignored him and trotted off and that is the ONLY reason we made our flight with just a few minutes to spare. So, my advice is DON'T BELIEVE the Heathrow workers - question them, be alert and assertive if you have to be and ask other knowledgeable looking workers. Usually those with white shirt and ties. They will help get negotiate through the hoops to your flight.
It was very stressful for us and we will of course avoid Heathrow for connecting flights in the future.
Suzy