Hi Dan Patterson, thanks for the reply. The results from the mesh are a long flat plane, which isn't as expected. As mentioned I have no previous experience with this, so I'm not sure where the problem is. I hope you don't mind helping here.
I offered to create a DEM for a relative, to help them visualise a plot of land for planning purposes. I have a good amount of 3d visualisation experience, so I thought I'd find this relatively straight forward. The plot itself is very steep, and the surrounding area varies quite a lot, which is why I don't understand why I've managed to get a flat plane for my resulting mesh.
The OS map reference for the plot is SX2553NE, so I downloaded SX25 open lidar data from the governments website: Survey Open Data , and used the SX2553_DTM_50cm.asc file. If it wasn't for my complete lack of experience I'd assume that the height data was just plain wrong.