Best take cover Leon.
I experienced hail of this sort of size in Austria near the German border in the Berchtesgaden area around 2000 & Mrs B's R65LS tank still bears the scars.
The hail smashed the screen & cracked a fairing panel on my Deauville & smashed a spark plug cap and dented the tank on the BMW. The BWM was also blown sideways off it's centre stand & I was hit on the chest by a hailstone while picking it up - even through a BMW Goretex suit I had a bruise the size of a dinner plate. We had jumped over a barbed wire fence to get into a field to take cover behind a tree - the hailstones cut branches off the tree the thickness of my finger.
We went back into a small town we had just passed which had a bike dealer to get a replacement HT cap - utter carnage ! A McDonalds restaurant had all it's plate glass windows & sign smashed, the bike dealer had a row of new Suzukis outside the shop & all had been damaged, cars looked like they had been hit all over will a ball pein hammer & many had smashed windscreens & every tree on the roadside had been completely denuded of it's foliage, which lay across the road like a green carpet.
Yet 10 minutes later the sun had come out & the road was steaming in the heat. By the time I had gathered up a handfull of hail stones to take a picture, they had already melted to about the size of golf balls.
The R65 was fixed with a new plug cap & I gathered up all the pieces of my screen & bought a bottle of plastic model glue from a toyshop in Berchtesgaden to affect a bit of a Frankenstein repair to get me home. The R65 tank as not been fixed, as Mrs B thinks of the dents as being part of it's history.