Hi, I wondered if anyone could help me please. I don't know London at all really & need to get one of the high speed trains from Stratford International to St Pancras, however I find Stratford International station very confusing. Does anyone know which part of the station I need to go from (& do the platforms vary?) please. I know you can't use an Oyster card on this service so is it best to buy tickets online in advance, or get them at the station? I have no experience with train travel let alone in London, help please!