I have an advance ticket for a through journey via London, arriving at Paddington at lunchtime and leaving Kings X early evening on a Friday. I need to make a few journeys on the tube in London during the several hours between arriving at Paddington and contiuing my journey from Kings X. Tube journeys would be Paddington to Zone 2, Zone 2 to Zone 1 and Zone 1 to Kings X. My ticket is valid for one journey on thr tube from Paddington to Kings X, but I won't be doing that exact juorney. My query is, can I use my ticket for one of the other tube journeys, presumably in Zone 1 only? And even if it is supposedly valid, would it work the barriers at another station?