From information available the Model T engine may have been in use in a small light armoured vehicle from 1924 to 1930. (After 1928, other engines may have been used.) It would be an interesting academic exercise to see what the motor number (if used)and year is used in these vehicles.

And the articles it is stated that the engines produced 40 HP not the usual 22. Different rating system or improved engine design?

Carden-Loyd Mk.VI
The engine of Mark VI was Ford model T of 4 cylinders (on line), cooled by water, developing 40 hp to 2500 rpm. Mark VI had an autonomy of 144 km and could reach the 40 km/h on road. It could cross vertical obstacles of 0.41 m and frank cuts of 1.22 m. Mark VI was 2.46 m long, 1.75 m broad and 1.22 m in height and weighed 1.5 ton. The shielding had a maximum thickness of 9 mm. Under the radiator installed to the back, the hull ended in a reinforcement equipped with a hook of towing to which one attached a tracked trailer with two axles.

More Mark VI was used in various functions, more the transported loads were heavy. To compensate the increase in the weights, different engines were tried like Meadows of 4 or 6 cylinders or Armstrong-siddeley cooled by air.
http://www.wardrawings.be/WW2/Files/1-Vehicles/Allies/3-UK/07-Others/Tankettes/File/Carden-Loyd-Tankettes.htm

I suppose the engine would be of whatever year was current. Ford continued making Model T engines for years after the end of car production. The 40 hp rating may have been achieved with a high compression head and other accoutrements some folks still put on their stock Ford blocks for more power today.

I thought the tank had two engines side by side? There may be some of those in front of American Legion Posts still, might be worth inquiring?

In 1918/19 Ford did produce a twin engine light tank with available parts and a drive train from the new production TT truck.

Thanks to Adrian Whiteman, New Zealand it has come to light that other countries after WWI began to develop their own light single engine Ford T tank.

A search of the internet lead to the above attached information that there was other versions of Ford powered military stuff.

It appears these machines were around in various names and countries.

The HP quoted probably isn't brake HP but notional HP calculated from cyl bore, like the RAC HP system which was used in the UK to calculate annual tax. 40hp would tell me it had 2 motors of 20hp each.

Here's the link to the Tank Museum's Carden-Lloyd here in the UK, which is specified as Model T motor of 22.5hp

https://www.tankmuseum.org/museum-online/vehicles/object-e1952-26

Oh, and a message to the tank driver shown, from the Battalion Sergeant-Major -

YOU 'ORRIBLE LITTLE MAN! GET YOUR 'AIR CUT!

If anyone would read the site: http://www.wardrawings.be/WW2/Files/1-Vehicles/Allies/3-UK/07-Others/Tankettes/F ile/Carden-Loyd-Tankettes.htm
The horsepower rating is from 14 to 40 horsepower for what appears to be a single engine vehicle. Of course, there may be a question in the translation of "What the heck is a cv (chevaux vapeur) ?"

OK I have read the document again. The French produced a sleeved-down version of the T engine to reduce its taxable HP to 14, this was also offered in the UK. That could be the motor mentioned for the MK 1.

The MK V is mentioned as having 22.5 hp. The MK VI is mentioned as 40hp but that could be a Model A motor. There are some possible typos in this document, e.g. the text for the MK I mentions 14hp but the spec sheet says 40hp; the text for MK V says '22 of 5 hp' where the spec says 22.5hp. And, yes, French taxable hp (cv) is calculated slightly differently to English hp. The motor in the Tank Museum's Carden-Lloyd looks stock Model T.

And the engine number is? It may make no difference. But is it a UK motor number? And if possible is it a clue to determine what year of production?

If nothing else, it is an addition to the trivia of the Model T.

Call me weird but I kind of want one now.