Using low res input data with a high res model still produces data

Using low res input data with a high res model e.g. UKCM2a-0-HH still produces output data. However the output data is still low resolution.

A fix would be good to prevent people trying to produce high res outputs with low res inputs in future.

No file, test, or entry point is named. Start by reproducing the UKCM2a-0-HH case with low-resolution input and a high-resolution model, then locate the validation or processing path that allows it. Done means the incompatible combination is rejected instead of producing low-resolution output.

Written by the indexing model from the issue text.