In reply to DaveHK:
We're not really worried about people sharing the information; some determined folks will find ways of doing that no matter what, and trying to prevent them from doing it would inevitably harm our legitimate customers (and probably not actually stop the determined folks anyway).
A big reason we changed to a subscription model was because the buy model was too expensive for most people. Paying £25 for a digital guidebook just seems like too much money in this world of 99p apps, but £3 or £4 a month for access to everything seems like a bargain (unless you're only interested in a small fraction of the content, admittedly).
The ultimate aim was to open the app up to more people. By removing the point where you have to decide to drop £25 on in-app content, we hoped that the app would become more useful as an addition to owning guidebooks, which has a broader appeal, rather than a replacement, which only appeals to a few it turns out.
So far the response has been very positive, and we hope to be able to grow the user base to a sustainable level, but it's clear that subscription does leave people such as yourself out in the cold.
The unfortunate reality is that we don't have the resources to implement a buy model to go alongside the subscription one (like in iTunes). I'm sorry about that.