Hello
As written there are too many sets of quotes, like this:
"C:\Users\Ian 4q1\bin\arm-none-eabi-objdump.exe"  -h -S -l "C:\Users\Ian il_winder.ino.elf" > "C:\Users\Ian il_winder.ino_objDump.log"
it works. This is the string that the build was producing in the build window when the listing fails

Further investigations yesterday:

For some reason my windows session had .log associated with notepad. Removing that file association and running the build produced the full disassembly listing as it was supposed to in the disassembly window.

Changing any of the optimization settings to "no optimization" and cleaning the solution screwed it up bigtime. There were a number of compiler error to do with the programming port and obviously no disassembly file. I think that maybe the subject of another topic at a later date.

Changed the optimization back to "default optimization" then doing a project clean produced yet another variant. On the first build all there was the usual .elf error and no disassembly listing. The usual long command as above was listed and no .log file produced. Running that long string in a cmd prompt produced the file. 

Running the build a second time produced the file in the disassembly window but only the first part of it. There was a message at the end of the listing with something like " the full listing is available at...path to the .log file"

Other observations are that it will not build a release version of any optimization form...there's a plethora of linker errors to do with debug code (which I guess is because it tries to link with excluded code) Not to worried about this as Arduino studio builds it fine and  it's  probably for another topic once the listing file is fixed.

Hope that helps