Hey Glenn,
I had most of the leaves fall off both my limes and both my buddhas hand.
I think it was because we had such a wet winter here in NZ!
They have since the last month or two grown all their leaves back and are looking v.healthy with lots of new growth.
I just picked up a Chinotto from Kings Plant barn last week and and has NO new spring growth on it yet so maybe that variety may be a late bloomer?
It also has plenty of flowers and little fruits.
My other mand3erines and oranges have just woken up and sprouted new growth just in the last 2 weeks also.
I'd maybe leave it where it is and hope for the best personally.
Maybe its a late grower??