Thanks for your help so far, i have figured out how to resave the epubs with covers but now have a bigger issue!
I have tried to import the epubs with covers back to my KT numerous times via 'send to device' and also just dragging and dropping and it gets stuck on 'processing content' every single time i try I only have 200 books, i do not know why it is taking hours to process the content.
I have factory reset 2x now and it still doesn't help.
Could editing on calibre have caused corruption of my kobo? all i did was add some covers.