[Arran]

Since it's a 1957-58 model it will have at least some paper capacitors, probably the Ero brand kind with the black ends. Another thing to be aware of in Grundigs is the plastic they used in the bandswitch assembly in some of their sets, they used polystyrene which can be attacked by some solvents.
One of the things that many German sets are notorious for is the way they incorporated the power switch into the band switch assembly, so every time you turned the set on you had to select a band, which would wear out the contacts after being used several hundred times. The band switch assembly is also mounted horizontally, which means that any dust or other crap can collect in the band switch assembly.
I never understood why they mounted the ferrite bar antenna on a rotating assembly connected through pulleys and dial cord to a knob on the front panel. It seems like a needlessly complicated gimmick.
Regards
Arran