do we have a use for the number keys within the basescape? if not, #1 - #8 could switch to the corresponding base... although we would need some kind of prompt that pops up if the chosen base either doesn't exist or can't supply the screen we are currently in (like for a base that doesn't have a workshop).
a smaller indicator could be used to show the currently active base in those screens, maybe a tiny row of numbers at the upper right corner with the "active" number highlighted? this would at the same time point the user to the fact that he can use the number keys to switch the active base.