Found this design and it printed well without supports.
However i found the plugs did not stay in the holes and the cable grip could damage the cabling on larger diameter cables.
I have added an original step file to help with anyone making your own changes. I found that the standard plug was slightly different to the adapter plug.
0.16 is 0.16mm is a reduction on the original of the plug walls and fitted the standard plug. As the cable was larger I widened the cable grip gap and rounded it.
0.21 is 0.21mm reduction on original plug walls and it fitted the adapter plug better. I also rounded the corners on the cable grip gap. No change to width as cable narrow.
ONSHAPE original file can be found here, Free account If you want to want to have access to files and make changes.
The author remixed this model.
Smaller gap for pins for UK plug