Well, today I've witnessed what I've been waiting for, as the plant has totally recovered (1 week later, and very suddenly)! I guess it was a combination between the unforgiving nature of a hydroponics system (in my novice hands!), and the shock of being transferred from soil (the way I did it), that made my plant look so sorry for itself.

Thanks for all the advice and I hope this thread helps others afflicted with similar issues.