Next year.
Ever since the Future Past Tour was announced I have been certain it will be very similar to the original LOTB. This year is very similar with the exception of the four dates later this year. Next year I think will be similar to 2019, and the question is if 2025 will be like 2020 was planned.
I don't see Bruce touring solo along side Maiden, absolutely not. So it has to be before or after.
For some reason I imagine he will tour South America at least, I can imagine he is very, very popular there. Europe is a given. He will also play much bigger places than British Lion.