Reading data with GMT.jl is now working!!
Note- you must install Ghostscript https://www.ghostscript.com/download/gsdnld.html
and the GMT software http://w3.ualg.pt/~jluis/mirone/downloads/gmt.html
before adding the GMT package.
In the GMT installer at the Choose Components stage check the DCW component also.
Huge thanks to @joa-quim for all the help.