Slitherine

It seems that a custom efx.pzdat file will not over-ride the one in the main Panzer Corps\Graphics folder. Is that right? I have a custom efx.pzdat in a custom campaign folder (Mods\Red Dawn\Graphics\efx.pzdat) but it won't function unless I put it in the main folder manually (or using the GME). Bit of a pain.

Yes, it's right.
You still have to use GME for the efx file.
And I think it's the best to be that way, until Panzer Corps begin to support cosmetic mods like sound mods.
Because if it was working, it would override GME, and in that case if you did want to use a sound mod for example, you would have to copy the sound mod to all the mods you might have in Documents\My Games\Panzer Corps\Mods. So if you had, for example, 5 custom campaigns you would have to copy 5 times the sound mod.

Yes, I see what you mean. I hoped that it would work the same as the campaign.pzdat; even if there is already one in the main Panzer Corps\Data folder the one in the Mods\ folder works. That way we could use the GME to enable the mod once, such as the sound mod, and have the efx file in each of the \Mods folders access it. Oh well, all in time.