The New Zealand Railway Corps Cap Badge

[Anzac16]

Hi !

I've not found any conversation about this badge and so I wanted to ask some help to learn more about it.
In a previous message about the NZE and Tunnelers badges, COREY showed us a picture with this badge.
Maybe its story is the same but I would like to be sure.

The only informations I've got are in "Military Badges of the British Empire 1914-1918" by Reginald COX.
So I know that this unit belonged to the New Zealand Engineer Corps and used to wear its own cap badge which was made in brass or in bronze for OSD.

Do you know how this badge was manufactured?
Probably die-struck like many badges, but maybe die-cast too?
The back of the badge could be flat?
What were the different types of fitment? (slider/lugs(and which type?))

If I'm right, as I read on the forum, most of the NZ badges were made by English makers during WW1 and especially Gaunt. So I guess this one could have been made by Gaunt too and can be found with the maker's mark or the famous tab on the back?
Maybe Stokes/Wellington/J.W. Tiptaft and Son made it as well? (like NZE badge)

If you have any pictures of this badge, front and back, I would be so glad to see them. And it's always easier to understand

Thank you very much.

Regards.