No - this plant is not entirely hardy, and because of where you are, cutting it down may encourage new growth, making it more susceptible to dying when winter comes, so if you want to give it the best chance of survival, just lightly trimming over the tips to remove spent flowers would be best.

I have one of these, I thought I’d lost it after last summer but I just cut off the dead bits and it’s back flowering again.

it's quite surprising how many hardy perennials were lost in this past winter in the NE of England but some of the more tender ones like the salvia survived (without mulch). Even a dahlia that I had forgotten to lift has grown again whereas the lifted ones didn't survive in the shed. That's the fun/joy of gardening I suppose!

You can blame the Beast from the East for that, Barbarak - just when plants thought it was safe to come out of hibernation and grow after such a mild winter, they got hit with freezing weather from March till early April.... Its certainly been a year of extremes now we've had all this heat and drought...