This is basically for anyone like me who got the game late, ran the trainer and discovered that it doesn't work - just makes sounds etc. Below, I will explain how to fix this. For the TL;DR version scroll to the bottom.
Before I begin, I'll just say that the trainer is not going to be updated again because of the fact the devs update it so damn frequently so releasing new trainers to match is a herculian task, hence the early retirement. So please do not ***** to admins about it because they have already done an amazing job and if you could actually be f*cked to read the rest of the msgs you could have found the solution. But I'll make life easy for you and put it here.
In essence the reason why it doesn't work is because the trainer and the game version DON'T MATCH! to make the final trainer 13.01.07.67 work, you have to 'rollback' your game version i.e. unpatch the game effectively to make the trainer version match the current version - kind of like downgrading your iPhone firmware so your jailbreak still works . So you're going to make the current game (which is around 13.07.somtething...) go back to 13.01.07.67 to correspond with trainer 13.01.07.67.
To do this, you go into the steamapps folder --> common --> WarGame European Escalation --> Data Here there'll be a whole heap of numbered folders. Each folder corresponds with a patch version. The one you're looking for which corresponds to trainer 13.01.07.67 is folder 670000683- just tried it and it works.
Go to this folder, and copy the version of Wargame that is inside. Copy and paste it in the main WarGame European Escalation folder where you found all the subfolders that say Data, Maps, Support and the most updated version of the game (the one which Steam chooses to run) Then run the game from there. If you try and run the game straight from the patch folder, Steam will say that it's 'missing an executable' and won't work. So just rename the original to Wargame 1 and copy the one from the patch and stick it in the main folder.
When you run the game, you may get a message saying that 'this version is not up to date, do you want to run a more up to date version?' but just click no and the game works fine.
I Have confirmed that the trainers work fine and my game hasn't crashed yet following my own instructions so I can't see why they won't work for you Enjoy this amaazzinngg game! And thanks for reading
TL;DR Go to: steamapps folder --> common --> WarGame European Escalation --> Data --> 670000683 Copy WarGame App there and paste in original folder. Run from there. Voila