I'm back from the client who lives next door to my late parents' house. And something to add to my earlier post.
This would have happened some time ago but I hadn't heard about it. I mentioned that the shed at the side had been replaced by a garage. The shed was made with asbsestos walls/roof with metal girders. The asbestos was removed leaving the girders. As a temporary measure, they put tarpualins over the girders to make it waterproof and used it to store surplus furniture from the house whilst work was being done inside (substantial work). Rubbish which had been in the shed and the house was placed around the back garden by the fencing.
One weekend the couple had gone away and the man's son stayed. He decided to have a bonfire in the back to get rid of the of the rubbish. All went well and he was then left with a large pile of ashes.
So he decided to collect the ashes and place them inside the ex-shed in case it rained.
Later that night my client was woken by the sound of fire engines next door. The ashes were still hot and the contents of the shed had caught fire, spread through the tarpaulins, setting fire to the rubbish by the fencing, and setting fire to the fencing itself.
The fencing between the shed and the neighbours was destroyed, as was the fencing at the back of the garden, as was some of the fencing along my client's garden.
I'm not aware that the fire spread to the house itself though so it wasn't as bad as it might have been.
The couple weren't too pleased with the son when they found out what had happened.