It was yesterday I posted! I had to edit a previous post instead of creating a new one, as I’d made 3 consecutive!
Interesting result! Trys asked someone do the filter calc for the existing values, so I’ll look forwards to going through this and checking the result, I should hope to get into this later today.
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@dbc No more consecutive replies, I’ll have to make economical use of the post count now. I can’t guarantee this will be the same as word count 
The VTx0.0769 come from where?
(Practice… No scanner available here unfortunately!)
I had a look at the CT input also, on second thought it’s incorrect to include the burden in the Thevenin equivalent. Therefore just having 330R and 220nF in the equation gives us 2190Hz, which could more closely match up swapping out the VT filter’s 100nF with a 8.2nF instead, 2030Hz.
So
VT fc = 2030Hz, and
CT fc = 2190Hz
What are the implications of this? Phase error…
2kHz seems a reasonable place to aim for, it’s been mentioned before as cutoff for electricity meters generally I think so I’ll run with that. I see in the SCT-013-000 datasheet the CT doesn’t capture much above 1kHz anyway. This will be a function of the burden value also.
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I swapped out the 100nF for an 8.2nF at the VT and the readings are back to normal!
Begs the question, why didn’t this show up before?!