Dear Helen
Thanks for the kind comments. I use a mag called Model Military International for a lot of reference - they have run a monthly piece on the Caunter scheme in Middle Eastern Command now for a while - this month is the Rolls Royce Armoured Car for example. I also used a good article following a guy putting a plastic kit together in 1:35 for detail and colour reference. I will dig out the mag and let you know the details. Just remember - No Azure Blue in the Caunter scheme if you want to be accurate.
As regards the 5.5 inch guns, yes they are Dinky, that is what we at Battlewagons do - reuse unlikely diecast toys amd models to produce nice objects for display or wargames. I have a few 5.5's in stock at present. They are £30 ea as finished guns excluding crew. Let me know if you want a few.
Here are some of my Artillery sets by commparison:


