Good morning Graham, Barry and Repassac
I have just set up a Homegroup on my Windows 10 computer (haven't added my better half's computer yet) and instructed it to share pictures, music and videos. Back on the Humax and 'hey presto' my desktop appears as Graham showed in his informative pics. I haven't gone into the detail yet because I am very busy today but I think the problem has almost certainly been cracked with all of your helpful comments.
I only wish Humax had pointed out the essential creation of a Homegroup in their set up instructions. Hopefully this will be the end of this issue so thanks all of you, over and out.
Jonathan