Liverpool = wc:UKXX0083
I got the code by entering Liverpool in the 'metrixweather city name' box in the weather settings section of the mymetrixlite plug-in.
Once you have entered your chosen city press 'check id' (blue button) and the plug-in will change to your city, then green to save.
St Helens doesn't appear to have a code..
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found this page
https://weather.codes/united-kingdom/