Just to restate what I know, and that the items are to the best of my knowledge not available through RAFM any more.
Someone on another forum intimated that the Type 19 was withdrawn from production because the pressings started to crack. My case was exactly as Alex says, I picked up a job lot of headgear inclusive of Type 19 from a guy leaving the WW2 side of things.
Stephen is always busy (a testament to his work really!), not only from new items being made but from people like me who break items and send them to him for repair!