Record Temperatures & UHI

I don’t disagree that the site of the Stevenson screen hasn’t moved since previous records were set. In fact the UHI is included in the definition of a heatwave in London being 3 degrees Celsius higher than the definition of a heatwave elsewhere, specifically > 28 degrees Celsius in London cf >25 degrees Celsius elsewhere, including Birmingham, Manchester, Leeds and other major conurbations, for three consecutive days.
As I understand it the heat wave experienced across Western Europe was caused by an area of high pressure at altitude which increased the pressure below it by the downward flow of air, thus increasing the temperature through an adiabatic process.
When I was growing up in the 1960’s the national paper I looked at always listed the warmest places across different parts of the country, the one site that was invariably the warmest was Heathrow. Some of the issues with the siting of older weather stations in the U.K. was because the meteorological office came under our Ministry of Defence, which means that the measuring equipment was placed on RAF stations in the days of propeller powered aircraft which didn’t require huge runways. Of course those weather stations have remained pretty much where they were originally located, despite the changes to the aircraft type. Also, when Heathrow was chosen for the weather station it wasn’t the main London airport, which was actually Croydon.