The Met Office are still playing the odds (60%) regarding the chances of a new record UK all time high on Thursday.
This forecast temperature chart is about as close as you'll get to viewing any detailed UKMO mesoscale NWP products.
I wonder if engaging in speculation about exactly how hot it's going to get is their primary purpose these days?
I suppose extreme weather events coupled with AGW keep them all in a job, and what better way to fuel Joe Public's appetite for it, than heatwaves such as this.
I notice in passing that the German ICON model seems to be forecasting slightly lower temperatures for Thursday afternoon which if it comes about would be an absolute disaster.