I'll note that even though they have one of those Adobe Digital Editions link-buttons on the download page, the actual e-book is DRM-free ePub.
Even though I don't usually read romance, I do encourage free giveaways which are also DRM-free and require minimal hoop-jumping to get them, so

to Mills & Boon for that and their
Everyone's Reading site, even if they're probably never going to put up that promised mystery 12th book, just to keep people checking.
Thanks OP for sharing!