Andy Evans wrote:

Since the morons who designed the socket failed to realise that there is a very
limited supply of rectangular hole saws, this requires us to either bodge or
look for a punch that costs less than £40. Any ideas?


A Nibbler that attaches to an electric drill?
Beware, they do tend to run away but you could perhaps clamp
a couple of wooden strips to the panel to guide it.

Roger.