Exporting Sheet or Plan view to 2D CAD file

From a cutting plane view I've traced an orthophoto with CAD linework to produce a pictorial 2D elevation drawing. I now want to output this as a 2D CAD file from a Dynaview/sheet view. 

I select the linework in the sheet view. I then run the export to CAD command, and select appropriate format. View filter settings are set so that the relevant data is visible.

When I open the file in any CAD program (or reimport it as CAD to TBC) The border and scale bar display beautifully in model space (or layout/paper space views). But only the border and scale bar are in the drawing, the linework is not. The layers containing the linework I want, have not been exported. 

It is clearly selected, see image attached.

What have I done wrong? Is there a way in addition to the view filter, which somehow dictates what is exported to CAD from a sheet view despite being selected? Must I create a different type of sheet? I copied it to other types with the same result.

Please tell me how to output this sheet view to a CAD file. I have scoured the help. It seems like it should be obvious or easy to do. 

As a work around before I discover the solution, I have been exporting model space linework to a DWG/dxf and then 'flipping' it (Z coord becomes Y coord) so that it appears as 2D elevation in top view of model space. Alternatively I create a layout view in X Z plane in the 3rd party software.

However this method is time consuming & frustrating when the Dynaview clearly should be able to be used in TBC to do this, and output in a usable format 

I await your assistance, Thanks in advance

Ben