Classic British Flight Sim

This has probably been asked before, but is there a way to just toggle the instruments in the external view with a single key press?

I know you can define all sorts of cameras etc, but all I want is a simple on/off

I don't think so. Would be nice to be able to do that though.
BTW, have you seen the mod that adds back the shift-z readout in the top left of the screen as in fsx?

No, I hadn’t. Is it on the ms forum?

No, it's on flightsim.to.
https://flightsim.to/file/16358/shift-z-stats