DalesPlusFour shared some photos on his Factory Tour thread which shows the unit quite well.
https://i.imgur.com/1Lvr6ed.jpg
![[Linked Image]](http://i.imgur.com/1Lvr6ed.jpg)
or in close up is this bit
![[Linked Image]](https://tm-img.com/images/2022/07/07/Brakes.png)
I guess the two down pipes are the two circuits. The bar is the dual chambers as Luddite was outlining which is the culprit ?
I was going to make a joke about only having a single circuit leg to push it but that's probably only my sense of humour.
Love the colour on the Plus Four.