To be honest, that fact that digital textbooks are popular is not new. I've reported several times this year that lots of students here in the US are using but not buying digital textbooks, a trend which appears to be repeated in the UK. A Bowker survey from this spring showed an immense popularity for free digital educational resources, including ebooks and digital textbooks. A similar ebrary survey also showed that nearly half of UK college students used ebooks, though it didn't say what percentage were textbooks and it didn't cover purchase habits.
The survey results are available as in infographic below, and they also show that hardly any students buy all the required textbooks, a statistic which comes as no surprise.
But there are also several problems with this survey. For example, students are asked how they get their textbooks, and the only 3 options I can see are new, used, and other. This survey really should have included an option for borrowed, checked out of library, and OER or other legitimate freely available content.