Ok...Acorn should, perhaps, have made it clearer that only the first and final episodes are in colour. The series was shot in colour but the colour prints for most of the episodes would seem to have been junked and, clearly, no one felt this series justified the expense of restoration (all the prints are a little blurred and time-worn).
However, it's all about the drama/writing/acting, all of which is of a consistently high standard. If you don't know much about the origins of Rolls Royce, the life of E Nesbit (she didn't just write the Railway Children, you know), the origins of the Scout movement or Lloyd George's rise to power, this is a good place to get started.
Not all the episodes are of the same high standard: I felt the Conan Doyle one dragged somewhat. Best of the bunch, though, is Horatio Bottomley, with Timothy West cast to perfection as the charming rogue. The Daisy episode tends to be slammed but I was surprised to enjoy it....interesting experimental film techniques on show here. There's also a fascinating episode on the Music Hall Artists' strike of 1906, which 'features' George Formby Senior.
So, I'd urge people who enjoyed Fall Of Eagles and other contemporaenous BBC series to give this one a go...it isn't expensive and it makes for hours of absorbing viewing.