If it has heaps of new growth on it then there can't be to much wrong with it. Perhaps you should just prune off all the effected foliage and dispose of it in the bin just in case it is a fungal infection.

It's a delightful plant but like most eremophilas it suffers fungal problems in coastal areas. The symptoms you describe I'd consider its normal condition over winter. It should pick up thru spring. What I do is plant in a full sun, well drained area and mulch with stones or gravel to store heat overnight and to keep foliage away from fungal spores. Also I feed well to try and out grow disease, flat out or dead is the lot of these plants in conditions so unlike their natural ones.