John Spencer - Scootum

I've owned a 10' Scootum class sailing dinghy for over 30 years, and recently given it a ( more or less) total rebuild.
The design has always intrigued me but have found little information about the class.
I am looking for any information in the interests of preserving what anyone knows about the class.
Here's what I know or have learned. Any confirmation/correction or info is welcomed.

The boat was first built around 1960 in New Zealand.
Has a mainsail and jib.
Very light and fast.
Construction was cold moulded using two x 3mm untreated pine strips glued diagonally.
My understanding is that over 400 were built and the dinghy was very popular in Nelson and Canterbury areas of New Zealand.
I know of 2 surviving boats (mine being one), and it is rumoured there are another two in Christchurch.
I am told by a (now 79 year old) former professional boatbuilder, that he built one when he was 15 years old and the plans cost him 25 shillings (equiv to $2 or $3 I think).
He is very sure John Spencer was the designer, although i cannot find any supporting confirmation.
If my boatbuilder friend is correct, it means he built his boat around 1955 which contradicts my comment (above) that the class was designed around 1960.
I look forward to any info readers might have.