Thanks - no, it's not to do with normal availability coming up; just a trip I have booked but don't quite know whether I will actually take and/or if I take it, may want to come back to London significantly earlier in the day than I originally planned.
Seems I either have to cancel the entire trip (at least 24 hours before travel - not too bad as should know either way by then), but if I take the trip and fly the outbound I am then stuck with my booked return flight, unless BA decide to bend the rules (it might suit them in this instance to clear one extra passenger on the emptier early morning flights...) - but fare rules will have no flex so I should assume travel will be on the original return flight.
Thanks a lot