This is the only book you need. There are about 15 chapters. Work through 1 chapter each day, and it will only take you 15 days. The problem with alternative routes, is that you are learning more than what you need to pass. This book is written by the same people who set the test, so you’re not learning more than what you need to pass.
The Official DVSA Theory Test for Drivers of LGV / PCV
dsabooks.co.uk/product_info … cts_id=294
This book is also available on amazon and ebay, etc. so make a note of the ISBN number and that helps you get the latest version. The book is regularly updated, perhaps every year or two…which is why you want the latest version.