The beautiful fish vase - Oakpot can you help please

At Whangarei Antique Fair I came across this lovely vase. It is the only one I have ever seen. I didn't buy it... and wonder now whether perhaps I should have! Hopefully it is in someone else's collection by now. The seller told me she had found in in the Salvation Army shop, covered in tobacco smoke and grease. She cleaned it very carefully.
Anyway. Oakpot, would you be able to tell us where this blank was made, and some approx dates if possible.
It is a beautiful piece, and features in Gail Henry's second book.

Hi Maryr,
Extracts from Owen Salisbury's notes.

After Sparton Pottery closed in 1946, Norm Stevens a capable engineer who helped build the first Crown Lynn kiln knew about slip-cast pottery.
He built a oil fired kiln and started making pottery.Owen would drive to Henderson with a trailer to collect his ware and decorate it at the Royal Oak factory.

Cam Brown ( Sherwood Pottery) was making slip-cast pottery in a small electric kiln at Waitakere

My thoughts are the small items ie cacti pots were from Sherwood.The larger items ie the  fish vase came from Norm Stevens .Date appro.1949.

oakpot.

PS: I paid $135 for mine off TM + freight

Excellent information thank you oakpot.
Especially the mention of the small electric kiln used by Sherwood, which would certainly limit the size of the pieces made.
I think Gail Henry mentions Norm Stevens in her books and I will check that out too.
You certainly don't see many of these around and they are really quite unique.

Thank you very much for that info Oakpot.
That vase is a real treasure.
I should have bought it!
All the best
ValM