DalesPlusFour shared some photos on his Factory Tour thread which shows the unit quite well.
https://i.imgur.com/1Lvr6ed.jpg
or in close up is this bit
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.
Everyone loves a Morgan. Even me, unless it's broken again.