The hat should be the colour of the uniform as painted, but the uniform should be the colour of the hat! In WW I British & Commonwealth/Empire forces' uniforms were khaki drill (anything from fawn to red brown)
Mike
No Mike. Tony is correct. The AIF uniform was a dark greenish Khaki, and not tan or fawn. Very clearly seen in the displays at the Australian War Memorial. The hat is too fawn - see the hat in my initial post which is Great War vintage.
Cheers
Chris