So, after spending an hour trying to sort this out, here's the steps that worked for me:
  • Ensure you have Adobe Digital Edition installed
  • Disconnect your Cool-er eBook reader - it doesn't need to be attached at this point
  • Buy eBook in ePub format from Waterstones (actually don't cos the process sucks, but if you have already...)
  • Click Download
  • File downloaded will be something like URLLink.acsm
  • Click on this file, the eBook should then open in Adobe Digital Edition (you may need to authorise Adobe Digital Edition)
  • Go and get a beer, you've done well
  • Quit Adobe Digital Edition
  • Connect your Cool-er eBook reader
  • Open Adobe Digital Edition
  • Your Cool-er eBook reader should be displayed in your Library - mine appears as NTX_EB600
  • Select your eBook and drag it onto the eBook reader
  • Disconnect the Cool-er eBook reader (which in itself is a challenge on the Mac as it remounts itself constantly)
  • Look on your Cool-er eBook reader - your newly purchased eBook should be on your Cool-er device in the Digital Editions folder
  • Go and get another beer and enjoy your book

This really shouldn't need a blog post of instructions, it should just work, but it didn't, and that's hugely disappointing. I want eBook readers to work - this is my first purchase (I've only read free eBooks up until now), and I wanted it to be smooth and lovely, but it wasn't and it cost more than I could get it via Amazon in print. *sigh*