Hmm... A little more playing and I find if I right click on a line of the box the option for 'line' comes back... It seems strange that there is a different, less options, dropdown menu if you click inside the box (which I swear was giving the full list of options) against clicking on the line.
Ah well! another of life's little tribulations to exercise the more mature mind.
Thanks for looking, all seems now to be well