This certainly sounds strange!.
With respect to the local Authorities, it was stated that 4 tests were done, but it does not say which tests were done.
Having investigated Electrocutions before, I would like to know WHO performed the said tests, if they were Qualified to perform such tests and also if these tests were referenced to any local Earth point.
Lamp-posts are, by thier own virtue, Earthed(Grounded), I would be looking at the fence!.
Let's face it, these days if you're not young, you're old - Red Green