Thanks Stefano,
I had looked at Sogo around a year ago, and found that I just couldn't get it to work well enough, it seems that since then, It no longer requires customised plugins for thunderbird and should work fine with just lightning.
I've also tried getting Kronolith going, and it works fine within webmail, but I can't for the life of me get it to run via lightning, or outlook.
Anyway, I'll have another crack at SOGo, and report back!