Hey. I'm sure it'll be simple but I just can't work out how to move all markers in unison.

I nudged all my audio to make space for a longer intro, but the markers didn't nudge with the audio. They are all ok relative to each other - I'm just looking to 'select all markers' then nudge them by a few bars.

Thanks in advance.

Your error was in nudging your tracks.
 
If you'd chosen Project > Insert Time/Measures you markers would have moved with the clips (along with Tempo changes, Meter/Key changes/Envelopes etc)
 
As it is, I don't know of a way in which you can automatically move all of your markers in one go

Thanks. Found a way:
Select/highlight whole timeline
Edit => cut special
Ensure only 'markers' are selected
Move now time to desired position
Paste
Be happy ;)