I've finally sorted out the colour patch decals. I made my own!
I purchased a few sheets of decal paper, downloaded Inkscape and a few hours later I've got a sheet of decals for the 3 battalions my great-grandfathers served in.
I also made some trench map decals to go on the officer's maps using a scaled map from my 'Mapping the Front' CD.
If anyone is interested I can upload the sheets.