I have 3 of these available all in remarkably good, probably never issued vintage condition. 
I am not sure about the size since I dont really understand the dutch label (see pictures if you can understand them).
I think its a medium but here are my measurements:

Shoulders 17"

Length 31"

Sleeves 25.5"

Chest (under arm to under arm).  21"

I will ship fast and with care.