Oh yes - that's right, the skeins aren't the same colour. It wasn't at all obvious before knitting but there is a big difference between the dye shades in the different skeins. I'm using hand-dyed silk (from HipKnits) which doesn't have dyelots so maybe it shouldn't be too much of a surprise but I'm a bit miffed! The second skein also appears to have a significantly greater yardage than the first, I've already doubled the length since the first skein and there's a fair bit of yarn left to go.
My current plan is to check the three remaining skeins, find the darkest one and use that for the other end. If that creates a pleasing symmetry then I'll leave it at that, if not, then I'm considering dying the wrap with a similar shade of blue to even the blocks out.
The actual knitting is going well - the silk is lovely and soft (though very heavy) to work with and the beads aren't bugging me as much now as they were during the first skein. You can just see them hiding in the middle of the cable. NB the colour in the top photo is a much better representation that the second, but I couldn't get the detail with the flash on.