Thanks for the replies!
It was actually for my mate to play against his son with the option file.
Any idea how my mate & myself can play a co-op game as teammates? Was having a nightmare last night! I saw the "Clan" option but no idea how to actually set it up?
Thanks again!
With regards to you and your mate playing via the clan option, are you both in your own separate homes trying to play online or are you both on the same console? I know how to do the clan match if you are both in your own homes on separate consoles but it had me confused at first.
One of you create a clan and then the other one should search for it and request to join (because I had no idea how to invite someone when I created mine) and then the creator should look in requests and accept the request. Anyway once that is done, select online co op and eventually you will get to a screen that looks like a lobby with loads of rooms created. This part confused me when I first saw it because I wasn't sure if me and my mate were supposed to try and join one of those rooms or create our own. The answer is create your own anyway.
On the setup screen for your room change the security to 'clan members only' (assuming you accepted your friends request to join the clan), you can then access some settings to pick the team you want to use and there is also a screen in there where you can 'Invite' from a pop up window (it's the bottom option). You could also just tell your mate the room number as well and he could scroll down and find it, which ever is easiest.
Once your Gamer Tag and your friends are visible in the room just click on the big START MATCH button using the X button and it will start searching. It will then find you a game which will be either 2v1, 2v2 or 2v3 (mostly 2v2 in my case though) but as long as you're on the same team that's the most important thing. To be fair it is a much better way of playing co op than the awful lobby system of 2017. Hope that helps.