I have not seen 1917 but have been told that the Sikh soldier is part of a white unit or a least around white soldiers. If this happened it was rare and so rare that you could accuse the film of forced diversity for finding a way to show it. Laurence is correct.
Like the journalist sarcastically said I have used google. I came straight to wiki the worlds encyclopedia and what a surprise there is little to no information about this but it does mention what I already know, Sikhs were in their own battalions, they were not mixed in with white soldiers and 'one of the lads'. I would imagine language barriers would have been a problem not worth creating by mixing the Sikhs with British soldiers.
So it's debatable whether a Sikh would be anywhere other than in a Sikh battalion and it does look like Laurence is right that it's forced diversity but what if he is wrong?
I believe we should be free to have conversations and think out loud, be wrong and make mistakes. I know it's hard for the guardian types to understand that.
All around The Guardian office, blood pressure rising, and swivelling eyes darting about on protruded stalks. Keep up the good work, Laurence.