John Rumm wrote:
So while you are correct that we know what it mens to be competant in a
technical sense, I am not convinced that *anyone* actually knows what
that means in a legal sense.

It was mentioned earlier. If you do the work, and it's fine,
you're competent. If it is not OK, you are by definition
not competent. This (competency) id referred to in all sorts
of regulations, not just for gas work.