Greetings @DAStroudGIS
Was the service published by you? If not, do you know who the publisher is? Apparently, the service in question seems to be a cached service created from a Mosaic Dataset (MDS). For some reason, the path to the images in the original MDS was no longer current when the cache service was created, which results in the checker-board pattern that is seen when zooming in beyond ~ 1:3,000.
If you have access to the original MDS or know who published it, you may want to suggest they revise the paths to the original images in MDS and correct them. Please see Repairing paths in a mosaic dataset.
I hope the above is of assistance.
Miguel
