I understand from Marc at the Furness Wagon Company that the following LDEC wagon kits are (or shortly will be) available:
15ft 5 plank open
16ft 5 plank open
16ft box van
16ft 3 plank drop-side (Labelled Taff Vale Rly)
16ft 10ton Brake van
This is practically a whole goods train all in one swoop! I hope I need not tell anyone reading this that these wagons all became GC property in 1907. Although, obviously, they would have taken a while to repaint and some would still have been in LDEC livery for a while.
Furness Wagon Company are on the web and also often attend Exhibitions, especially GOG ones. Their kits vary in complexity, as is explained on the site.
As an aside, I should mention that there is some debate about the LDEC wagon livery. Dow says chocolate, but there are other sources that say grey. So take your pick, unless anyone has definite information. "Chocolate" in early 20th Century terms does not necessarily mean what we generally mean by "chocolate". It could be "lake" as per LNWR coaches, which look brownish or reddish according to light - and perhaps the viewer's colour perception.
So perhaps GCR grey is safest after all.
By the way, good luck finding photos of these prototypes. They are rare at best, and for some, like the brake van, make hen's teeth look relatively commonplace.