Good evening: I am travelling from the South West to Watford Junction via Paddington on an Advance Single. The travel itinerary routes me to Paddington on FGW then via the Tube to Queens Park then Overground to Watford Junction, do I have to go on that slightly bonkers route or can I take the very sensible route, Tube to Euston and fast train London Midland train to Watford thus saving me an hour of my life. Thanks.