Matthew ,
Joking aside , many locos were exported from Britain in the heyday of steam , and right up to the end of steam they were still being exported . The problem was , especially in the early years , a group would float a proposed rail link , get the money , order the bits ,and then go bust before taking delivery .
The loco builders quite frequently then sold the affected loco or even locos more cheaply to get them off their hands , thus some enterprising business chappies . not caring too much about left or right hand drive , bought in the locos satisfied they had a bargain .
They say beggars can’t be choosers .
Before the USA entered WW2 , pretty well all the British Commonwealth , to their everlasting credit ,
came to the aid of the Mother Country who in turn ordered large quantities of road vehicles from the USA . No frills , we need 'em fast , just send what you make already --so although all the Commonwealth affected , except Canada drove on the left , they happily accepted vehicles for driving on the right . Most were then marked "Caution , Left Hand Drive " on the rear --presumably
so you knew which side to hit it to hurt the driver . No , it was because hand signals were normal back then.
So there is another example for you .
The annoying thing is , I cannot for the life of me remember if the USRA tanks engines supplied to us in WW2 are LH or RH drive .
So , Matthew , there you have an explanation of some of the reasons for wrong hand drive . There is also the silly one --true , but silly–whereby some ex colonies , out of pure childish spite , went wrong handed just to show their independence .
Mike