This is my favourite patch of dock (YELLOW DOCK). It is my own vegetable garden that I discovered as I was out walking a very long time ago. It comes up again a number of times a year and I have picked from this patch OFTEN. At this time of the year if you look closely you will see the young, shine curled up shoots emerging. These are my favourite. They have a slightly lemony flavour you won't find in the other dock varieties.
Dock is a go-to in salads or stir fries or whatever, for anything green, added to lettuce or whatever other greens you are using.
There is a caution here. Dock contains oxalic acid (also found in spinach) and "sources" say you should not have too much - whatever that means. However, blanching removes the problem, so blanch any that you use, just before you use it.
Added to parsley and other lovely greens, it makes a wonderful pesto. I am sure you have a favourite recipe.
Here is a tip. When you make pesto, make more than you need, and put the left overs in ice-cube trays and freeze it - when frozen, turn out, bag, and put back in the freezer. You will always have just the right amount for pasta for one or four, just defrost the exact amount of pesto you need.
DOCK is also a plant that the colonists used to use instead of rhubarb. Use the leaves in salads, steamed or stirfries, and cook the mature (sometimes 3ft high) stalks with a little sugar (as you do with rhubarb). Delicious.