Hi Joe and welcome, the Sprite was one produced by Healey Marine between 1960 and 1962..I think. It was a copy of an american boat designed by Bill Tritt around '58/'59 and made by Glasspar called the G3. Donald Healey had it copied, but modified the sponsons. Healey75 has one and has all the salient details re Healey Marine and will pop his head up here. There are another 8 we know of, 4 belong to members of the CMBA, with one running at the moment and 2 in restoration this year.
The moulds were sold on and produced by Interglass, with the same centerdeck as the Healey, but different details and a rear bench seat. Their model was called the Thunderball and announced at Earls Court Boat Show in Jan of 1965. There are 2 of these in the CMBA, with a few that have come up on ebay. They can be confused with the Healey as they look intrinsically the same. The moulds were then sold on to the Birchwood Boat Company and announced at ECBS in Jan of 1968. Their model is called the Thunderski, without a centerdeck and normally with 2 back to back moulded seats . I have one below, with a 1969 50hp Mercury on the back; is my pride and joy....
The moulds went under some development as the floor was lowered and a well added down the center line, perhaps to store skis...there are another 2 of those in the club...the cheapest was £2.57 on auction (Se7en can correct me..).
Here endeth the lesson...

Attach some pics if you can...we like pictures here.
Pauca sed bona - Few, but good.