I can thoroughly recommend this book. All B&W photos but a fine work depicting the area in the early days of diesels. A few blue ones make an appearance but mainly shown are green diesels , a lot without even warning panels. I think (haven't checked) all the photos are credited to Dr Ian C Allen, a quite a few have been seen previously in his 1980s book Diesels in East Anglia. This is a bit of a treasure trove for a much neglected area in railway photography. There are great shot of a loco hauling just a couple of wagons, an this is brilliant inspiration for the railway modeller.
Tony