I am on a website to check fares from London St Pancras to Leicester. I want to buy 2 round trip first class tickets for my wife and adult daughter, and return the same day. This website asks if you have a rail pass. I will have a 4 day BritRail England Consecutive Senior Pass. My wife and daughter will have an oyster card. If I say that I do not have a rail pass, the fare is Usd $ 163 round trip. If I say that I do have a rail pass, the fare is Usd $ 22 round trip. Would a London 7 day Travel card work as a rail pass. Obviously, I am trying to get the discounted rate from London to Leicester fairly. Can I make the decision to buy either an oyster card or 7 day London card when I arrive Heathrow, or will this just not work? I will have several days in London before we go to Leicester. I have asked this question earlier, but I do not think I was clear. Thank you.