Hi Gordon,
Yes, you're probably right concerning the shield, probably the heat is coming from below. But you know what? it's funny, when I bought the car 4 years ago, I don't remember sensing this smell. Before the car was restored, there was one day when I was driving a bit harder and just before the curve, I shifted down 1 gear, but it jumped to neutral, and then pressed on the accelerator hard. The pipes that come out the engine shroud came loose and the car drove some miles in this condition a few miles. The engine was breathing hot air for a while, hhmm?
After this I never stopped sensing the smell and I also started having problems with the idle point, but these were the only effects that resulted from this episode, since it never lost performance. The idle problem was solved recently, it seems it the carb needed to be tuned, but the smell was never solved.
Could this be related?
Well, concerning the weather around here, this has been a weird summer, some rain, but then again no fires, so it's not all bad. It's starting to get colder sooner than normal too, but it's still mild for a walk, at least in Lisbon (center of the country). If you go south, probably it will be better.
All the best.
Miguel