I now have the book (£8 from Amazon instead of £25 from the Beeb/OU).
You are apparently very chuffed, chuffed!

Not as as chuffed as me because I will borrow it from him for free!

I too thought it a really first class programme and learned things I didn't know which is always a bonus. The production values were high and the research up to the standard of something part financed by the OU.
My only irritation was with the director who seemed to insist that when not engaged with each other, the presenters talked to someone just off camera and not to the viewer. Not sure what that was all about. Nevertheless, a most enjoyable series, which no doubt contributed to the coffers of the large number of heritage railways that were used.