If you expected that there would be a strong correlation between temperatures from the daily central England series and the monthly values from the UK gridded 1910 data series then you would be right, there is, a very strong one. I’ve never compared charts of both before, so here are graphs of the 12 month moving averages from both series for the last 30 years. I could run a more detailed analysis to find out the exact correlation figures, but I don’t have time to write code to combine both data sets and the graphs will have to do. The one thing I did notice from a quick look is the 30 year linear tend in the CET series is running at +0.11°C per decade, and the one for the UK 1910 data is up at +0.18°C, now why is that? Perhaps it’s because the CET data is for a much smaller area compared with the area of the whole UK. I could run it against values for the Midlands region but I already know that linear trend for the gridded 1910 data is similar at +0.19°C per decade.