We are going to a few things that are part of the 2 for 1 deal, so the math works out for us. I guess B1G1 is a thing where I live and not as popular elsewhere.
We are coming in thru Heathrow on the Heathrow express so we will get our travelcards when we get to Paddington Station.
We will have our passport size pictures as well. Anything else I am missing? I tend to worry about the little things and they bother me until I can figure it out, so thanks for all the help.