Here is the link to the contingency planners forecast for Jul / Jul-Sep
https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/business/public-sector/civil-contingency/forecast-temp-jas-v2.pdf
Fig T3 shows the data points from the models for July 2019. The mid-point of the range appears to be in the upper 15's which is somewhat below the long run mean.
My analogue analysis looked at years where May and June were both close to average. Since 1950 this gave 8 matches. There were 5 years below average with a CET between 14.7C and 15.9C (1958, 1961, 1974, 1978. 1980). Two years were close to average at around 16.8C (1969, 1997). One year was very warm with 18.6C (1995). So overall a general signal from both the analogues and the contingency planners forecast for something a little below average if you look at everything in the round.
If we expect the matching back beyond May we find that 1961 and 1997 are the best matches to 2019 as Feb, Mar and Apr were all warm in these years. 1961 had a cool Jul CET at 15.2C and 1997 was close to average at 16.7C.
1997 is clearly more representative of modern times and the general warming trend. The model output at the start of the month, as per post 1 of this thread also pointed to something average or slightly below.
Given all the above and the fact that the last two months have been close to average, I decided to go for another average month with my prediction of 16.8C.
Full list of predictions coming shortly.