London Control has no weather radar whatsoever (according to them). The only way they know where there is bad weather is from lots of airliners asking for "30 degrees right" etc.
This isn't the USA
A stormscope is good in the sense that if it shows clusters of strikes, you really don't want to go there. But then one should plan the flight level so as to be in VMC - right up to close to the aircraft operating ceiling if necessary. Then you can avoid CBs visually.
Personally I would not fly in IMC, with CBs forecast, using the stormscope for CB avoidance.