Another mystery engine competition

Thanks, David, for releasing the vacuum on this mystery.
However, wisps are still swirling in the background.
There are plenty of Cherub pictures on the 'net, but - they are all the other way up!
Inverting the engine for its ABC role would surely have played havoc with its lubrication arrangements, and more.
Also, aircraft engines have always been designed with, primarily, reliability in mind, and secondarily, a good power-to-weight ratio. Actual power per cc. scarcely came into it.
So how wise was selection of this engine for automotive duties?

Paul,

I think that all of the pictures of the Cherub engine are for the Mark 3 version but the Mark 1 was the other way up.
I still can't work out the valve arrangement as the later pictures do indeed show a rocker with the adjuster but it is relatively short.

As it was entered in the 200 Miles race reliability would have been more important that maximum speed. Dixon used a CR of 3:1 in one race (1921 500 Miles?) race for reliability and won.

Hi Roger,
Thanks for the update/correction.
Reliability? David writes that it broke a crankshaft!
I have to think that each of those long 'pushrod' tubes contained, in fact, the central (rotary/oscillating) part of a special, much-extended rocker.
No great puzzle about how the outboard ends worked. The inboard ends could each have been activated by a face cam on a common shaft.
I wonder why Bristol decided to turn their engine upside down.

I found that Milntown does not have 1923 Autocar vols so could not investigate further.
Of no relevance at all but a great find, in an earlier volume this delightful Edwardian advertising card seems to have been left as a book mark for over a hundred years.

Is there any other reference to the Cherub engine being used by cars?