Yes, why not. You can cut them like baby leaf salad and hopefully keep cropping them.

Interesting - all lettuce is not the same from a nutrient point of view. The most nutritious lettuce is Romaine, followed by Cos, Iceberg is the worst. There isn't that much difference between spinach and romaine lettuce in terms of nutrients other than twice the level of iron in spinach, but a world of difference between either and Iceberg, which is mostly water, so it rather depends which lettuce you were growing/eating.

If you want to grow spinach in the ground, try sowing it again early autumn for picking over the winter.

Thanks B for your suggestion, on my last try at growing it in late Spring I made a special, small raised bed about 4 ft x 1ft, filled it with decent soil and set spinach seeds at about 2 inch centres ( not knowing any better ) but not one came up. So in late September I'll try again in the same place.
Is there any particular seed you'd recommend that produces lettuce- like leaves ? As usual I haven't a clue.

You can buy cut and come again lettuce in seed form practically anywhere. I used to plant them in seed trays a few days apart and had lettuce all summer long.

If you mean spinach to use instead of lettuce, any old spinach is fine, its just its usual to crop it while the leaves are relatively small to use as salad leaves. Larger leaves are usually chopped up and cooked

Got it B, thanks. Have also noted your info about Romaine lettuce. As long as it doesn't taste like Rocket which I dislike, I'll be growing it next year.

Ugh, rocket, I loathe it too, seems to be in everything these days... there's another bitter one, can't remember what it is, mizuna maybe

I love rocket and corriander. I can't get enough of it.

You have a weird sense of taste C, just like my daughter's.

Rocket and coriander, dear lord - all you'd have to do is throw in broad or butter beans and it'd be my worst nightmare - I'd rather starve! Weird how we all differ in taste, but probably a good thing we do...