Unexpected car diagnosis

My car has been making strange noises for months. I had no idea what the cause was, but it didn't sound like a serious issue. It just sounded like some loose panel or something. And the car was handling fine!

When I walked back to my car after the award ceremony of the Trawsfynydd race, I saw something move underneath the car. Hmm! That might be something amiss. So I got down on my knees and had a look. And there was some aluminium panel that had broken loose from one of its fixings, and it was flapping around in the strong winds. That must've been the source of all the noise!

Not the best pic, but you can see the loose sheet, and the bolt with rusty washer that used to hold it. And a strip of the blue car that contained the helpful men! 

I intended to just take a picture of it and send it to Martin. He knows about cars. He would undoubtedly be able to tell me if this was a problem or not. But two men who were about to leave as well saw me stare at the underside of my car, and asked me if something was wrong. And they offered to have a look.

They said it was just a heat sensor. A heat sensor? It was just an aluminium sheet. But they did say it was ok; it would be safe to drive like that. And one managed to more or less fix it back into position. The sheet had torn a bit, so I'm sure it will need replacing in the long run, but this guy had clearly managed to fix it so well it would get me home.

Martin called it a heat shield, which seemed more logical to me. He also didn't seem worried. I suppose I might have it dealt with the next time I send my car for a service. At least I now know what the issue was!