I need to be able to purchase a Tesco SIM card and will be traveling from Heathrow on the Piccadilly line to where I will be staying. I know there is a Tesco Express at the Turnpike stop, which is my final stop, but don't know if those carry SIM cards. Would a Tesco metro be a better one to go to? If it is, where is a good one near the underground Piccadilly line? I will have my 9 year old son and luggage in tow after a long haul flight so it would be nice if we don't have to walk too far. Tesco has the best pay as you go SIM plan for what I need right now, that is why I need to go to them.