On Mon, 14 May 2018 10:11:05 +0100
Robin wrote:

On 14/05/2018 03:36, Rob Morley wrote:
On Sun, 13 May 2018 09:41:31 +0100
Robin wrote:

[...]

So run the test load through a power meter?

Yes, and as Adam said you can get an analogue one of those for less
than £20

https://www.tlc-direct.co.uk/Main_In...#Credit_Meters

No, one of these: https://www.ebay.co.uk/itm/142794183077