As mentioned it won't be covered by BWC, but it's an Avios redemption so you can cancel for £35 per person. You might as well book as the downside is very limited.

Japan is, I think, the only major tourist destination apart from mainland China that has not even spoken about a schedule or roadmap for reopening for tourism. I'd hesitate to say it's likely they'll be open as normal by November, but you don't have much to lose by booking it.