On Thu, 30 Nov 2017 11:39:17 +0000 (GMT), charles
wrote:

snip

I took the tester home last night and I too got a reading of 238-239V
went down to 237-8 when boiling my kettle. Even the 51Hz went down to
50Hz but then again I don't think such small changes mean much as the
unit samples at about twice per second.


If your test meter thought that you boiling a kettle dropped the mains
frequncy from 51Hz to 50Hz, then it's a very strange meter.

His meter didn't, he did. ;-)

Cheers, T i m