It doesn't appear to be a Z fighting issue,If I select the face with a crossing the properties say that its a single entity and if I delete it a hole appears.

The original texture map was derived from an "A1" size pdf that was exported as a jpg at 150 dpi so that would make it approximately 5000x 3400.

I had a reoccurring issue with a recent LO project, Several times on update the texture map on the ground plain disappeared. This was an orthographic photo of the site. Even re-inserting the scene from the SU model didn't work, I even started a new LO project and the the map would still disappear. The only work around was to open up SU and send the scene back to a new LO project. The SU model was large - 43 meg in size and the LO project ended up at 33 meg.

I don' think the system is the issue, I run an HP Z600 Workstation (64bit) Intel Xeon X5550 @ 2.67 GHz with 6 GB of Rom and a Nvidia Quarro FX 4800 graphics card with 1.5 GB on board.

Has anyone had similar issues? I use a raster setting while I work and update manually.