I don't think it's been as bad here in Sheffield, but it's still the driest summer I can remember since I moved here over 10 years ago! (This is definitely a good thing in my part of the world - I'm sick of washouts!)
We've had a lot of rain over the last week and everything has perked up tremendously. When you do get a good old downpour, it will come back! In the meantime, you can go in with the secateurs and reduce the size of any plants that are really suffering to help them through the stress.