The promised photos:
Sorry for the poor quality, these were taken with my mobile phone in poor lighting...
As you can see, I used grey heating pipe insulation. Black would have been better, but I had these collecting dust in the basement, so I used them.
The black background in the VW logo is not solid but a honeycombed grill (you can see it in the second image if you look carefully) so the upper grill is not completely blocked which is a good thing for the intercooler and the AC radiator behind it.
For the lower grill I have to think up something else since the pipe insutlation does not fit.
BTW, this is my warm parking spot; you can see an air duct in the upper left corner of the first photo which emits air with 26°C. Outside temps are around 4°C at the moment, this should also help FE :-)
so long,
tinduck