Sorrel and chervil?

Wherever I tried today I could not get sorrel ( which was optional to the recipe) or chervil! But went ahead anyway with Roast chicken, herb and asparagus rice.
This was a recipe to use left over roast chicken but as I had not prepared for this I had to cook some chicken instead.
Lots of herbs in this one, some from my home grown ones, some bought and some completely un obtainable!!!
A light refreshing sort of dish , useful if trying to use leftover chicken but otherwise wouldn't do this one again if it meant actually cooking soe chicken first.
Why is it so difficult to obtain ingredients, my friend who lives down south has none of these problems!!! Are all the good cooks in the south- I don't think so !!!!!