Lanscape textures and layers.

So It’s been a good years since I’ve done landscapes in UE4, and it seems some things have changed. At the moment, I’m trying to apply a material to my landscape by using a bitmap and splatmap generated in world machine. I have successfully done this technique before using landscape layer blending, however trying the same method all I get is a black material. Has something changed recently in an update? Basically I want my bitmap as the base texture, then detail textures/normals (grass, rock etc) to be blended in using the splatmap as an RGB source for placement. Like I said, I have used this method before and it was relatively straightforward, however it doesn’t appear to work. In fact, even using the landscape layer blend node at all doesn’t even work when trying to use just one texture. Any thoughts on what is going on? Or any work arounds? Any help is much appreciated. Thanks.