Object axis/dimensions getting reversed

Blender 2.82.7 in linux and I have a 93MB blend file made up of 400 objects.
I want to export the individual objects to be able to use them in another project however,
When I select an individual object (and I am careful to check the Selected Only box) and do Export/Import, this works fine but in the new scene although the axis is the same and the object measures correctly, the Dimensions of Y and Z in the Transform box are reversed.
If I change these to read correctly the object gets distorted.
In the screen shot

Y should read 280 and Z should read 48.3

Any advice greatly appreciated. Thanks

PS: Just imported the next object and it is placed correctly in the new project but again the Y and Z figures in the Dimensions box are reversed, which is likely to cause me a real problem down the line

You can choose which axis is up when importing objects.

It’s in the transform tab in the right panel in the Blender View File window opened after doing File > Import > Wavefront (.obj). To unhide this panel click on the gear icon on the top right area of the header.

Hello birb
I confess I had missed that option but having tried it, it makes matters worse, so that is not the answer.