When you open the site it will show an image of the earth with the O Degree InfraRed cloud image overlaid. By picking the region as 'Western Europe' you should zoom into the UK. You can zoom in more by using the plus button on the left hand side and dragging the image to centre the UK.
While the IR images show the (ordinary) cloud there is no information on how high it is.
There are a couple of products that give a better view of how high the cloud is. The first is the CTH (Cloud Top Height), clicking on the toolbar button that looks a bit like a pen on a sheet of paper will show you the legend that shows which colours relate to which height.
You can also change the date and time in the toolbar to look at historic information. This only goes back a couple of weeks. It is instructive to look at the images for the 9/10 June 2019 when NLC was spotted from some parts of the UK. I am quite suprised that it was clear enough - The NLC must have been above the other cloud in the image.
Another image that can be of some use is under the RGB Composites tab. This is the 'Fog' image that shows low cloud in green tones and higher cloud in red (at night only).
Have a look and let us all know how you get on and if you find any other useful images.
Unfortunatly NLC are too cold to be detected by the IR detector on the spacecraft. Even the long wavelength is tuned for 200 to 300 K when the NLC are below 150K