I LOVE pickles, so when I lived in the UK last year, I about went mad trying to find suitable ones for a decent price. The best thing I found was from the kosher section in Sainsbury's...but I think it was around a quid for tiny portion (maybe 5 small gerkins). Anything from the 'pickle' section was always gross - check the label for SUGAR and VINEGAR. In REAL dill pickles, these 2 things are a no-no and any jar with them will not taste right.
Honestly, the best pickles I found were from Subway - since they were exactly the same! I always meant to ask them where I could get some (or if they'd even sell me any!), but I forgot.
If anyone finds some in supermarket chain, please let me know. I'm moving back over in a week, so I know the desperate search will begin again soon! (I resorted to just bringing over jars with me from the US last time around...and prayed they didn't break in the luggage!!)