Which 1967 booklet is this, please David? I am not familiar with it, (but obviously interested!).
In think that unless Flamingo carried a bulk in Willow Wren service mote than once, it is unlikely this picture was that early - the evidence seems to be it was very much towards the end of Willow Wren CTS days, probably when Ron Withey worked it..
One mystery though, is that in other pictures I have seen when it has a bulk, it is paired with a Star class butty, (probably Cygnus?). If the boat behind Flamingo in the picture I have posted above is its own butty, then it is a Town class, not a Star, and I have no idea which one.