I will be arriving at heathrow with 11 year old and staying at hol. inn kensington. I am going to purchase an oyster card with 7 day travel card for myself. I plan to use "kid for quid" daily ticket for my 11 year old. If I load extra money on my oyster card, can that be used to cover cost of ride for both of us to hotel from airport or do I have to purchase separate pass for 11 year old for that trip and how much will it cost?