Jacques Torres Chocolate is the best according to most consumer reviews. Others in a descending order include Byrne & Carlson, Candina Chocolatier, Martine's Chocolates, Fran's Chocolates and Confections.
I have not eaten bad chocolate--here or there (except for some I bought after a holiday on sale that was OLD and should have been thrown away, not sold. Everywhere I've gone in other countries the chocolate most often served was Swiss (I don't know the reason.) I have to admit I've not been to England, so I've not been Cadburied. However, this time I'm going to agree with Melloblue--Ghirardelli's at the top, and Hershey's any day of the week.
Well English chocolate is amazing. We think Hershey's and guitars LI is great. You have never tried chocolate from England. I wish they sold it here in America. Well here in America I agree with mellblue and Barbara-ghiradelli and hersheys at any time anywhere.