I went to 'File' in the top of the window menus, then to 'Import bookmaks and settings... ', then to to a pop up windows which suggest 'Mozilla Firefox' Now dont be fooled by that !! It has a pulldown menu option on its right hand side. The only option that actually works is 'Bookmarks HTML file', so select that now it does offer an option to find the file, I had put it in Desktop.
Then proceeding arrives with something you can get to with clicking on the 'heart shaped ' ikon.
So I'm very happy ! Thank you very much with your help which shopped me giving up !
I've no idea why the 'firefox' option failed completely.
I looked in root/usr/share and could not find the folder in which Opera and its data/bookmarks is kept. so could not just plonk the bookmarks straight in.
Hope this will be useful for other users of Linux Opera.
So delighted I've got a faster and now relative tame Browser ! Well done the Opera Team !