[Lynn Eades]

Colin, I think you will find that the VLT Mk 6B all had the wide horned track. (was Australia the only purchaser of the the Mk 6B?) they are from 1935-6 approx.(you tell me?)
Later (1938) the Australian Government bought one of Carrier, Armoured M.G.No2 Mk1 (Machine Gun Carrier) This was built by Nuffield (Morris) Its British numbers were T2831 and HMH384.(Ref. Nigel Watsons carrier books) This was one of Britian's earliest production standardized carriers. T2831 was the first of a batch of 150 M.G. Carriers
Mike Cecil's Australian Military Equipment Profiles Vol.2 refers to it as a "Bren No2 MkI (This info was not available to Mike at the time of printing)
Anyhoo, moving on.
Australia then built 151 LP1 carriers taking the wide track idea from their currently "in service" VLT Mk6B tanks (except that at some point, they changed to the lead plug retainer from the headed pins)As every one knows, this then carried over to the later LP2 and then the LP2A. Later those building the Windsors and T16s saw the stabilizing benefits of the wider rubber and adopted the idea.
I believe that that an upgrade was considered in British carrier production, but was rejected as it would complicate (wait for it!) the supply chain.