Skoda Scala Gearbox Slipping

Sounds like a transfer case issue. I had similar gear grinding and unclean shifts with my old Volvo. Check for any transfer fluid leaks. Have you inspected the transfer case oil?

Oil leakage I have not checked, but the transfer case oil, no. How would I check it?

On the Volvo, oil leakage was a big clue. Also, if the transfer case oil is dark or has metal shavings, it points to defective gears. Your best bet is to get it checked at a workshop. They'll diagnose the issue properly.

Thanks for the input. Took it to a local mechanic and it was indeed the transfer case. Gears were worn. Cost 330€ to sort out.