There are a number of sources for weather forecasts nationally and locally. It is probably fair to say that most pilots will not rely on any single source but rather look at multiple forecasts and decide on the most likely scenario on balance.
There are links for national weather forecasting websites on this page.
There are also links for weather forecasting websites on this page and also several general forecasts for North Staffordshire and the Peak District.
The use of forecasts on mobile devices is also very useful as is sharing forecast and live weather information via Telegram groups; the PSA has such a group.