Hopefully of interest to most on here.
My book 'BR; From Green To Blue' is out shortly, it's a photo book, 160 colour shots with captions all about the changeover from green to blue liveries (and from black and maroon too) and features shots from 1964-87, predominantly from 1967-73.
You can order it from https://shop.keypublishing.com/product/View/productCode/B700/BR: From Green to Blue Book