Ok, I have solved it, the solution is as follows for anyone else wanting this kind of thing.
As JX53mb suggested the gamemode can fire ticks when paused, so I created the blueprints to create the countdown UMG on a custom event in my gamemode blueprint and enabled the tick when paused option in details.
Then in the menu UMG I used a GetGameMode and then cast to my specific gamemode, then I dragged off the object pin and called the event.
Simple when you know how. Now I can use delay and other stuff in conjunction with my UMG (although it is a bit of a workaround).