Material Mapping distorted

[Anonymous]

I am having trouble with materials on a particular job, refer to the screen shots below. As you can see the blockwork is fuzzy in one and clear in the other. It isn't just the blockwork, some textures/walls the texture is blurred/fuzzy others it is clear. I have found if i draw a short wall, it appears correctly, if i draw a long wall it is very distorted. What could be causing this? i have tried everything, So far the only fix is to merge or past the model into a new file. That appears to fix the problem, however when i open the file a few days later (the new file) it has reverted back to the distorted materials.

Suggestions, it's very frustrating when you need some 3D stills/walkthroughs.