I can't help much Murray. All the frames I came across were 7000 nos, circa 1973/74. So thats about halfway thro the prod'n run between circa '63 & '73.
On another note, I did come across a news item in Jul/Aug 89 Classic Racer announcing "pre65 Sprite Scrambler" frame kits, "replica of 63-68 Sprite frames, to suit Starmaker, T100, Maico & CZ engines".
Built by Fred Giles, Workhouse Corner, Cornwall.
Ring any bells, Mark?