Hi Geoff,
It had to have a new driver as the original one's voice coils packed up. After doing a bit of research i found it was quite common on the "Blue Line" drivers as they were basically a cheap Italian speaker. After more reading of users on-line a few people said to upgrade it entirely, so i decided that rather than do a like for like swap and possibly be in the same situation again, to replace it with a better quality name brand speaker. So it now has a new Eminence Kappa inside and sounds a whole lot better for it.
Thanks for your question, Mike.