I'm looking at travelling from Tottenham Court Road to Hayes and Harlington next Friday evening (around 20:00 ish) with 2 adults using a two-together railcard. For some journeys the forums ticket site is offering me a £14.50 anytime day single (for 2 people) and others an off-peak day travelcard for £20.80 (for two people). Am I missing something obvious why the anytime day single is not valid on the all the departures from Tottenham Court Road?