Thank you for your response, the process for adding palettes is not very intuitive, but I appreciate that it is possible.
When I put color A on my canvas, change the color choice to B, then want to go back to the color A, I use the color picker to get A, again, and it shows correctly at the top right where you see the round preview of the selected color, A. All good.
However, when I go into the wheel to adjust the shade on the gradient, the wheel gradient is not the same color as A, it is a slightly different color (eg choosing a teal from my canvas, but the wheel is more slightly blue, not the correct teal). I must then find color A by sliding the wheel until I just think it's close enough. This is a bug and needs to be fixed, as we should be able to get the "picked color" from our canvas, to the color wheel, itself.
Does that help make more sense?