skimmia flowers are scented and slow growing. Some of the Daphne's are evergreen and again flowers are scented. Cant think of any more offthe top of my head. Viburnums?

Rosemary or lavender.......some of the herbs like the sages?

I have a Daphne in a pot which is covered with pink, extremely scented blossoms, just about to open. The nice thing is, its one of the only flowering shrubs in the late winter. Of course it can be planted in the garden, but I don't have the space.

Pittosporum tobira. Must be planted in a sheltered area.

Thanks all, you lot are just brill.

Managed to purchase 5 Sarcococco from Earlswood nursery today the scent is awesome.

Only just seen this question. How about artemesia abrotanum? Aromatic foliage (if you rub it between finger and thumb) and you can make little bags like lavender bags to deter moths. It makes a low neat bush which you can cut hard back every spring if you wish. Oh drat, just noticed you said evergreen and they aren't.