Paul and I went to talk to the gentleman at the print shop:

1. The problem with the over-cropping was caused by the pages being printed on stock which was a bit too small, to save a bit of money. They've promised they won't do that again, so that problem should be gone. I asked about the implications for price, and was assured that they're negligible.
2. The problems with colour are (we hope) solved. We compared Pantone swatches with the original volume 12 cover, and settled on Pantone 299C for both the solid band and the French text; we're pretty confident they'll look good, and close to the original volumes, without the cost of an extra colour.
3. We reworked the cover using the new Pantone colour, and Paul did some sterling work creating "knock outs" for the text which prints over the solid blue. The details are beyond me, but when I come to edit this next time, I need to make sure that any text I change is also changed on all the layers below it. This applies to the English journal title, the word "VOLUME", and the years. The cover is now ready to be sent to the printers.
4. The problem with pages being slightly offset in the last volume is apparently unavoidable. The cheap laser printing that we're using is simply not as accurate as a traditional printing press, but it's not economically viable to use a printing press until the numbers are in the thousands. I guess we just have to live with that, but I know other journals suffer the same issues.

So we should be good to go tomorrow, barring any overnight changes to the text.