Related to this, would an Anytime Day Single paper ticket to Zone 6 (ZONE U1256 LONDN) be valid to Heathrow Elizabeth Line?
This is £6.70 from e.g. Wapping.
Just to make it extra confusing, LU single and return tickets (such as the one you suggest) are valid on the Elizabeth line between London Paddington and Abbey Wood, but not between Hayes & Harlington and Heathrow Terminals. The rest of the line it's pretty ambiguous. I probably wouldn't use one but you probably would be fine to.
U zone tickets are a real odd one these days, being automatically valid for London Underground and the DLR, and parts of London Overground that used to be London Underground, or are shared with it still, and on the other routes where LU tickets are accepted by National Rail services in general. But generally they're not valid on Trams or Buses. Generally they're actually accepted by London Overground more widely than this too, because it's a logical interpretation they'd be valid - but they would be very unlikely to be accepted on Elizabeth line services to Heathrow Airport despite the same logic applying. They're the
only single and return tickets available for a journey like Chelmsford to Bond Street, but they're not permitted for Chelmsford to Heathrow Terminals, making exactly the same journey, but staying onboard the same train for longer. The full Heathrow Express option is the only through ticket available for that journey.
U zone tickets including the relevant zones can of course be used as usual to Heathrow Terminals by the Piccadilly line, though.
