The changer looks like "All Pull" to me. Possibly styled after early Sho-Bud?
https://www.thebritishsteeliessociety.co.uk/viewtopic.php?f=40&t=15152&p=62648&hilit=all+pull+changer#p62648
Diagram 3rd from the bottom of the above post.
Pull release changers don't have have the split pivot arrangement, just a one piece solid pivoting on the axle.
https://www.thebritishsteeliessociety.co.uk/viewtopic.php?f=39&t=16219&p=67108&hilit=pull+release#p67108




