There shouldn't ever be a smell of burning insulation: fuses are supposed to stop that happening.
A 2007 Roadster: does that have a fuse box under the dash, or are all the fuses in the electronics box under the bonnet? I know my 2009 had everything in the electronics box.
I also know that there were 2 fuses protecting power to the instruments and dash and both had to be OK for the car to start.
If the fuses are under the dash they all need checking, or preferably replacing. If the burning is one of the fuses then you have an idea of the cause.
If there are no fuses under the dash I'd take the dash off and check everything for signs of burning, before checking and replacing fuses in the electronics box.
Actually I think I'd probably get the car collected by a dealer...as has been said, the last thing you want is to have to re-wire under there.
Good luck....
