I think its probably got something to do with a route I downloaded but when I loaded my own route the green default ground texture had changed. I really want to change it back, what's the setting I need to adjust please?
I've never had this problem before, I don't even know what I did to make it happen. I downloaded a route that had the pbr grass but the same thing happened, the grass you see in the second shot had replaced the darker pbr grass.
Are you using a Region asset? Open the Route Editor (in the Edit Menu). What region has been set? This will define the default ground texture or default ground grid pattern.
You can create your own Region asset or edit an existing one to set your preferred ground texture and then assign the route to that Region.