On May 27, BA from Toronto, Canada (YYZ) to LHR terminal 5 arrived at 6:35am. Once we landed, we used a bus to get to terminal 5, up a few escalators, through a kiosks for immigration, picked up our luggage, all by 7:15am. I think having the bus helped without having to do the the long walk and timing, we missed the crowds. We had a 9:45am National Express ticket to Southampton. We could have gotten on an earlier Coach with no change fee. I was waiting on my sister who was suppose to arrive at 6:30am at terminal 2 and be on the same National Express Coach 9:30am from terminal 2.
My sister’s plane was late leaving their home airport my 2 1/2 hours so arrived 2 1/2 late at terminal 2. She had the long walk, about 1 1/2 hour for kiosk immigration and luggage pickup. She missed her 9:30am National Express ticket and was able to get on a later Coach with no change fee.
You never know how long you have to wait to go through immigration and luggage pick up. Plan for 90 minutes.
At the airports, National Express will let you get on another Coach if there are seats available with no change fee.. Take a note of National Express schedule if late or early so you can get on the next Coach.
Why not use a car service to take you from LHR to your London hotel? They wait outside the luggage area with your name on a sign and take you direct to your hotel after a long flight. They monitor your flight arrival times since you give them the information. They cost more than National Express but worth it have a long flight.
I have used www.justairports.com from LHR to London hotel and from hotel to LHR 4x.