Ok thanks. So it turns out that it's not working as I don't see that on the version number, so I'll try to install it again.
As it happens, I tried again, thinking that 'maybe' it's installed and I managed to get past the fort anyway, but I lost everything but 4 guns, so I had to rebuild my entire army from scratch, meaning that the next battle was equally impossible.
I realise that Legendary is extremely difficult. I'm happy to get my butt kicked, but I'd like to have it kicked on different maps I might try the exploit just to get past the fort, but I'll try to get the mod installed first.