I have always wondered ...

[A G Wood]

'In the days when I traveled to and from Cambridge to Dundee for University I used the hand throttle on the A1. In the winter I could then put my feet on the gearbox for added warmth.'
When I was an apprentice, I used to sometimes cadge a lift home from Night School with a classmate who owned a Model A  truck, a close cousin of the one the Clampett (Beverley Hillbillies) family drove. He always used the hand throttle on the motorway to avoid  getting warm feet, apparently a real issue on the RHD models due to the closeness of the exhaust manifold.

[Greig Smith]

On long distance trips in summer with our RHD '28 Model A, I drive on the hand throttle with my right foot holding the driver's door open against the airflow to try & get the hot air out the cockpit. The brake & clutch pedal get so hot you can feel the heat through the soles of your shoes

Aye
Greig

[Bill Sheehan]

Monsdonnet - back to your comment that Austin admired American ideas, our friend Herbert was quite friendly with Henry Ford and visiited him on more than a couple of occasions.  And because Stanley Edge got a few ideas from Austin's Hudson, it's possible Stanley suggested the "Gas" on the lever?   Cheers,  Bill in Oz