My experience was a bit like the video over Kent. I was flying solo, IFR from Troyes to Lyon, 4 years ago yesterday. The wifi in the terminal was down, and I had left my mobile phone in Oxford earlier in the day, so I couldn't check the weather myself. However, I got a briefing from the Meteo France office on the airfield about half an hour before takeoff. The forecaster's weather radar was unavailable, but she said that there would be no storms on my route - just some rain for the first half of the flight. She was wrong!
I took off, straight into cloud and climbed to FL90 in steady rain. It then got very dark and the rain became extremely heavy. There were very strong up and down drafts, but fortunately only moderate turbulence. It became darker still, the rain became even heavier - by far the heaviest I've ever experienced in flight - and there was a bolt of lightning just in front and to the left of me. I heard the thunder clearly. The radio was unreadable with static, but I figured it was better to bust an IFR clearance than continue into a possibly worsening storm - so I turned back, announcing blindly that I was returning to Troyes. As I came out of the heaviest rain I could hear the controller again (he was quite unconcerned about me turning round).
Fortunately the clouds broke close to Troyes airport and I could cancel IFR and land.
I stayed overnight in Troyes, and from the hotel could download a weather radar image for the time of my flight. I had flown on a track of 190 degrees from the red dot - not something I would have tried if I'd seen the radar before departure!
At the time I was as current as I have ever been, and possibly as competent at IFR as I will ever be. It was a most unpleasant experience, and I'm not sure I'd manage it as well today. Fortunately access to real time weather information while travelling has improved greatly in the last 4 years, so I probably wouldn't fly into that kind of weather by mistake again.
In the US, of course, the controller would have seen the precipitation on his radar and helped me to avoid it. Why can't they do that in Europe?