I have a polygon grid of a certain shape that has some data associated with it. Unfortunately its not properly projected, being in what seems to be an arbitrary scale and coordinate system (it was originally a DXF). I need to reproject this.

The grid cells are about 8 * 11 "units" (I'm going to guess metres - it looks like a "projected" system). I need them to be 3000 * 4000 metres (OSGB).

How do I reproject this grid into the desired new grid? Once its been "resized", I can then easily offset it to georeference it properly.

I have access to FME and ArcGIS.

Thanks