Follow-up:
I bought a Domi charging cable from eBay because at a glance it looked like it would fit my camera instead of buying the expensive 'official' Canon power lead.
This is the cable I received:
https://tgigi.com/search?q=domi&options[prefix]=last
As luck would have it - it DOES fit the camera, and cost much less than the $39.99 some other sites were charging for a Domi lead.
It is just a simple USB to Barrel lead, there's no electronics inside it.
Barrel Outside is electrical Negative.
Barrel Inside is electrical Positive.
I took a few dimension measurements for the barrel in the photos below..
View attachment 93666
View attachment 93667
View attachment 93668
The Camera connector has a 1.5mm pin in the center and the barrel was a good fit on it.
Any pin from 1.5mm to 2.0mm should fit the barrel.