Salad Leaves and Calabrese

Hi,

I have a couple of questions I hope you can help with! Firstly, I've got some salad leaves, using them as cut and come again, but now they have all shot up one thick stem and have started to flower (bolting?). I've nipped off the flower, but should I cut off the whole stem? Or should it just be left?

Secondly, a few of my Calabrese plants have several small holes (a bit bigger than a pin prick) in them - is this normal or is something eating them? I haven't seen anything touch them.

Once lettuce has bolted the leaves can become really bitter, so if I were you I'd pull the plants out and start some more off.
This is why succesional sowing is such a good idea, so you always have plants coming on ready to replace eaten/bolted ones, rather than have to wait for them to grow from seed.