I've a particular interest in all this as I've flown the Tokyo Haneda route on Avios several times, and have an upcoming trip booked.

So - before Covid it was easy enough. Be online at midnight 355 days out and book the flights - it really was that simple, providing you had enough Avios to book both. You could then phone up and get the return flight tacked on to your voucher (I used an Amex companion voucher).

It used to be the case that 2 First seats were released on most Tuesdays and Thursdays, and those are the ones I nabbed... three times I was able to do it, from 2016 to 2019.

That's all changed now, but don't lose hope. I had planned to return, but first the Covid shutdown and then an injury meant I had to keep cancelling flights. I booked (and later cancelled) no fewer than 5 return trips in Club World. In the meantime I kept racking up Avios, which comes in later.

My plans then changed: I would be getting a dog, but before that I would spend all my Avios on one last Japan trip. The snag was that (due to the nature of the beast) I couldn't book them a year out. My upcoming trip was arranged around 3 months in advance, and I checked diligently every day, multiple times, once I made my mind up to go. Nothing... so I signed up for a trial with SeatSpy. A couple of days later, one random afternoon, I had an alert - 2 Club World seats had opened up on BA8, the return flight. I booked them using a companion voucher. That then meant I needed flights out, but now I was restricted to certain dates (as I planned to stay there 6 to 9 nights). Nothing again... and the trial ran out. I still kept checking every day, and a JAL route via Frankfurt popped up. I booked it, but obviously it cost a lot more.

Since then I've kept looking, several times a day every day. To my astonishment two First seats popped up on the return (I woke up early that day and checked), but I didn't have enough Avios. I had the choice of phoning to modify the booking, or cancelling and rebooking. I chose the latter, as it would be faster - heart racing, I cancelled the Club World seats I had, waited what felt like 3 years for the voucher and Avios to return to my account, then booked the First seats - success! I had to pay the cancellation fee, but it was well worth it.

Similarly a few days later three Club World seats popped up on the outbound day. I cancelled the JAL booking and nabbed two seats, again it was a bit risky but it worked. I kept checking for First seats.

And then two days ago, it finally happened - four seats on the JAL A350 flight appeared. Very, very tempting, but as it's an evening flight it would mean losing most of a day, compared to the morning flight I had with BA. So I checked the day before and, remarkably, there were 2 First seats on JAL. Again, with my heart pounding, I cancelled the BA booking, waited for the Avios to come back, then tried booking the JAL seats. Emphasis on tried - it errored out. I tried a new tab, different browser, private mode - but nothing worked! I then went back to the original tab (still displaying the cancellation confirmation), tried again... and hallelujah, it worked that time.

So, I've done it - two seats out in JAL first class, two seats back in BA First. And in the interim period there were 2 Club World seats out, 2 Club World seats back, and 2 Business Class seats on JAL via Frankfurt. All of this has come and gone within the last 3 weeks, and that's just a few dates I was keeping an eye on.

The moral of the story? Even if you don't get the seats 355 days out, they can and do pop up at any time later on. For what it's worth, pretty much all the cancelled seats went straight back in the pool for redemption again, but the two Club World outbound seats I cancelled the other day didn't reappear.

PS - the official BA rule on tacking on returns to existing vouchers is that if the return wasn't yet released on the day you booked your outbound, i.e. more than 355 days out, they can add it on. If it was potentially available (as it would have been in my case), they won't.