My best guess would be somebody tried to "Austrianize" it, and back then red was ground by Austrian standards. Since that still leaves you with a black neutral and green phase (as opposed to black phase and grey neutral) I decided it would be wiser to put everything back to UK standards.
The kettle was a replacement for my most likely equally old orange and white plastic kettle from Germany. The element was scaled badly, so I tried putting in vinegar, sticking to the isntructions still stuck to the bottom of the kettle. Afterwards I had gotten rid of the lime, but apparently the plating of the element started coming off too and it looked rusty... besides I suddenly realized the orange plastic probably contained cadmium, so it retired. For some time I used a new €10 kettle, but it broke after roughly 6 months, and since the entire guts were just a big lump of PVC it was impossible to fix. Glad I got this one now!