Having done a bit of research it appears that coriander plants create new shoots from the leaf axils and can therefore be cut back to just above a leaf axil after which they’ll regrow from that new shoot.
This is exactly how some of my plants look. Others however appear to have no shoots growing from at least the first four or five leaf axils and somewhat predictably these are the taller ones that I’d like to cut back a bit as they’re getting rather tall and leggy, to the point where they’re struggling to carry their own weight.
So, as they’re liable to collapse anyhow, I’ve experimentally cut some of those back to a couple of leaves tall to see if that will promote some new growth now the original leader is gone and we’ll see what happens over the next few weeks.
In the process I’ve harvested another 25g of leaves which I’m going to credit to my winter salads experiment even though they’ll actually probably end up being frozen and eventually used in a curry recipe. That gives me a running total of 936g of salad leaves so far.