Summary

I've created hits model because I wanted an holder that would:

• make the plug hang downwards, thus protruding from the wall as little as possible
• be easy to insert / remove the plug
• cover the plug to avoid having debris/dust fall into the plug contacts
• provide support to tidy up the cable as well

I think this plug satisfies all these criteria. It does depend on the plug having a small "lip" that matches the holder. I bought my cable here:
https://ecoharmony.co.uk/products/32plug-lead-2f

Note that this holder was NOT designed to be used outdoors, as it has zero protection for rain, etc.

The model can be printed without supports by printing with the wall side facing down.

I've included the OpenSCAD source file to make it easier to remix.