On Sun, 10 Mar 2019 20:22:30 +0000, Bill Wright wrote:

The PAT test for extension leads comprises:
Test insulation resistance and polarity.
Visual check.

And check the earth is continuous from the plug to each/every outlet.
And check the fuse is correct
And fill in the Log Book of equipment. Or give them a written note if it
is only the one piece of equipment that you need to inspect.
You can also stick on a Pass label if you want, though it isnt mandatory.
But, if you fit a label, you do need the 'new' labels (new being 4 years
old now) that do not have a 'next test date', as the Tester does not
recommend the next test date now, and it should not be printed on any
labels.

Anyone could do that,...

Well, possibly, but it isnt as easy as you think if done properly, as you
have just proven.