Yep, that's it, made by many outfitters at the time. Very soft dull yellow-ish leather.
I haven't found a photo of one with all the details like von Schleich had.
Evidently the Germans thought the British leather coats were much better than the German ones. Later von Schleich also used an RFC Sidcot flying suit. I guess he was an anglophile where clothing was concerned![]()