Conway's has an "Official Artist's Impression" of a "1966 Light Destroyer project", flush-decked, which looks as though it relates to the design as enlarged but before the redesign with a forecastle, as in the pdf.
Displacement 4200t normal, 5000t deep. 425'x48'x22'
2 shaft, 2 Olympus, 2 Tyne 50000shp 30kn range 6000miles at 18kn
1-5"/54DP (2x2)-35mm Emerlec; 2x3 12.75in Mk 32TT
1 SM-1A RIM-66A SAM; 6 SSMs 2 helicopters.(Lynx)
Three to be built at Williamstown, keels laid from 1975, ready 1980-1984. Cancelled by new Labour govt 1973.
No mention of Gibbs and Cox. Design by Y-ARD of Australia.
It had certainly grown a bit. Hardly the original light destroyer, dimensions in my earlier post.