"Kingdom of Holland" is of course a misnomer
But yes, during the war, these were to indicate Netherlands personal serving in the British Army/RAF. Orange on uniform colour (khaki during the war) or light blue on air force blue.
After the war this was reintroduced in 1946, but in 1947 the word NEDERLAND was replaced by the motto JE MAINTIENDRAI. Orange (sometimes very light, tending to gold) on uniform colour (first khaki, then brown, now dark green, still light khaki on tropical dress). Sometimes embroidered direct on the sleeve, after all this was never to be changed.
Koninklijke Luchtmacht (Royal Air Force) stopped using theirs, date unknown to me).