Point Cloud height

Hey all, First of all! Thanks for this workflow, I think this will help me going forward. I do not have any experience with Cesium to date, I was awaiting this plugin for Unreal which I have been learning for around 9 months so far.
I have uploaded 2 LAS files ( Point Cloud ) which were then converted to 3D Tiles under Cesium Asset, they both appear in my Assets, they Both appear now in Unreal Engine, this part is all ok.
The issue I am getting is that the Point Clouds are indeed georeferenced, they appear fine in Lat and Long, but the Elevation of them is off.
When I turn off the Cesium World Terrain, and leave the Bing Maps imagery on, I can see that they are located in Lat Long, but when I turn the Cesium World Terrain, they are buried beneath this. Any suggestions really welcome.

Are they using the same ellipsoid height? Cesium uses wgs84 I believe?

I am using the Unreal Engine plugin too however the point cloud I added is not rendering. How did you get it to render in Unreal Engine? I added the LIDAR point cloud support plugin just in case but didn’t do anything.