Ok Guys, I have managed to sort it by trial and error. Removing plugins and extensions had no effect, here's what I did just in case anyone else hits this issue:
I located 2 directories created by kodi / xbmc during the plugin installation namely (hidden ) .kodi & and xbmc. These were on /media/hdd, although I've read that if you've installed kodi without a usb-stick or drive then these will be created on internal folders.
I then tried to remove these folders via filezilla and also telnet where I was getting errors, mostly read only errors. I finally removed the usb stick and fired it up in my computer where I could remove these folders with full access. Turned box off, inserted usb stick and fired it up.
Kodi then done a first installation again and after a few open and shuts of kodi it seems to be fully working again. Having to install a few selected apps and setting up trakt and realdebrid is a small price to pay for having this annoying issue fixed.
Thanks very much for replying and setting me off in the right direction