I have actually managed to stabilise the daemon now for the past 24 hours. I only post this as it may help somebody else coming across the same issue. I actually removed some torrents from trackers that I had not used before. I don't possibly know what issues those trackers could have caused, but on...

I am having the exact same issue as OP, although I have been running deluge on Ubuntu 12.04 with no issues for quite some time. Trouble commenced on the weekend when I restarted the daemon hoping to fix a troublesome torrent (would not go over 91.5% complete although it showed constant d/l traffic)....