Thanks both! The burning shame of knowing that I damn well scrolled right past the link from Berbster's FAQ post
at least twice is pretty severe - but nothing compared to the realisation that I've had movable markers the whole damn time and I just needed to press the Alt key to select them.
I swear, I'm not normally this dumb.
Thanks for your help, may your torps never be duds!
Cheers,
Dave