This basic question posed here has probably been discussed many times before, but here goes: My rather unique travelling pattern often involves a journey like this: Start from home at Basingstoke before 9am to go to Heathrow, fly to Germany, stay overnight, return to Heathrow the next day, then travel by train to a northern city eg Leeds. After a quick delivery there I either go back to home by the fastest train route possible, or stay overnight and go home early(ish) the next day. I work for a charity. They like me to save as much money as possible, and travel as fast as possible from Germany until delivery (within the limits of airline punctuality!). Advance tickets are not normally much use because my journey time back from Germany is not confirmed until late on the first day, and airline arrival times at Heathrow plus arrivals delays make the railways look like paragons of punctuality. I would like to use Offpeak Returns, say Basingstoke to Leeds, but that would involve an overnight break on the outward leg. I can get to Hayes and Harlington as a permitted route to London (Paddington) and buy a return ticket to Heathrow from there, picking up the Leeds journey the following day using Heathrow Connect and an East Coast train from Kings Cross. The wording in the CoC is a bit ambiguous about overnight breaks on outward portions of Offpeak Returns. What is the view of esteemed experts?