I was asked Jason for pictures of Irvin labels. I have put them here for ease of reference. They appear to have been made of cotton or linen. Here are a few.
1935 Irvin jacket
Wareing and Co trousers -1939 contract
1941 contract Irvin Air chute jacket
Late War jacket
1940 contract jacket by Links
1935 Irvin jacket
Wareing and Co trousers -1939 contract
1941 contract Irvin Air chute jacket
Late War jacket
1940 contract jacket by Links