I caved in. Despite the long TBR list, it's just too good a bargin to turn down, even though it meant jumping through way too many hoops...
Sign up for account, click buy, enter payment details, download book, book doesn't download. Realise I don't have ADE installed, go to download ADE, find you need flash to install it (if there's a non flash installer I didn't notice it and was losing the will to live by this point), install flash, realise you need an adobe account, sign up for account, install ADE, authorise my computer, finally download ebooks. Remove flash plugin. What a pita.
Compare that to amazon, sign up at amazon, enter payment details, click buy. download book.
Only part that wasn't a pain was dropping it into calibre, freeing and syncing to the kindle