The BBC stopped using the Met Office in March, so of course their forecasting has gone to shit. ITV weather is more accurate now.
Ah that makes sense, in a "Why the heck would they do that?" sort of way.
Just realised my post made me sound like I was in the Watford area! I was just using it as an example, I'm in the West London area, so I take the Central line into work and I'm constantly melting like the Raiders Of The Lost Ark when they open the Ark.