According to the Met Office, the highest officially recorded temperature in the UK was set at Faversham (Kent) back in 2003.
Faversham certainly appears to be in a hot spot, as it has regularly appeared in “hottest” lists since then. The same can be said of Gravesend, which is in the same part of the country.
Faversham has in fact only had continuous data since 1998, and Gravesend since 1995, so we cannot know if higher temperatures were set there in earlier years.