@Mrs_Often I'm afraid it's still not working
It's definitely the koboplugins.ini. and Kobo.tgz.that I'm manually moving to the .kobo folder, and it seems to install OK insofar that I get the updating screen once I unplug...it's just not firing up properly once I go in to a book and exit out of it...all very strange.
I don't want to pollute this thread with repeated requests for help, but will update if I make any progress from my side and can be of any assistance for anyone else with the same issue.