4th Battalion (Taranaki Rifles) Wellington Regiment Cap/Collar Badge

[stevjp]

Guys,
quick question.
When was the 4th Battalion (Taranaki Rifles) Wellington Regiment Cap and/or Collar worn?
Is it a Volunteer badge, pre-1911 for the 4th Battalion of the Wellington Regiment (Corbet kind of alludes that they changed their name to become post-1911 part of the 11th (Taranaki) Infantry Regiment, so then the 11th's badge was universally adopted?
Or is it post 1911, and they wore it as a distinction from their other comrades in the 11th, and until when (a hard to find badge, so I presume not for long)? Oldham has it in the Post 1911 section of his book.

Attached are a couple of examples of mine to show what I am talking about.

Many thanks in advance
James