If you look on ebay at JB Models/Airfix you may find some items you are after. S & M models do kits for mk1 and mk2 Alvis Stalwarts. Oxford models do diecast models of Landrover Defenders, Lightweights and 101s. For other vehicles check kit manufacturers like, Trumpeter, Dragon, Revel, Academy, Matchbox, Matador, Kingfisher.
My advice would be to get a pad and build up a list of required vehicles then check each manufacturers catalog or website and create your own reference list. Once you do that you could try the military modelling mags for kit reviews or articles.
I hope this is of some help.
Ian