Illustrator file not placing at 100%

[Michael5ED9]

Exhibition stand artwork

Illustrator Artboard: 985mm width x 2473mm height

InDesign document size: 985mm width x 2473mm height

The reason for the unusually large artwork size is because the Exhibition printer wants the artwork at full size for some unknown reason. Anyway, when the Illustrator file is imported into Id it's not placing at 100%, as expected, but at a fraction of the full size but the image is definitely 100%. The illustrator doc has 13 artboards (for side and back panels of the stand etc) and choosing Show Import Options, Trim and Page range are selected. 

Anybody know what's happening here or does Id preferences need deleting?

[Michael5ED9]

I've just done a test file with the same Id and Ai dimensions and simple colour fill box, same dimensions, and it imports fine so it must be something to do with the original file. What though?

[Michael5ED9]

Now copied a one panel to the test page (full dimensions) and it imports fine into Id.