Well, I've now managed to actually knit something from the yarn that I dyed, and on the whole I'm quite pleased with the results. The self striping effect worked far better than I had hoped, and I think that these little socks have come out very well.
As ever, there are a few little things that I would change next time I have a go at this, mainly the blue colour. Although it came out nice and strongly as I had hoped, it wasn't quite the shade of blue that I was looking for. I don't know if I can create that shade using food colouring, but I'll have to have a play and see what happens.
My next plan is to try a more random, variegated colour scheme, I think a mixture of yellows and oranges, quite subtle tones this time, might be nice for a few baby items. I'll certainly give the self striping a go in the future though.