Hi

I have a camelia. It is now about 7 years old and has always lived in pot. This spring it is not looking too healthy (see attached photos). A lot of the leaves are yellow/brown. We did have a cold winter. The leaves haven't fallen off and I can't see any pests/fungus etc. I looked on the web for common problems with camelias and it doesn't seem to be any of those. I think it may just be nutrient deficient as I hadn't changed the earth on the pot for 2 or 3 years. I've moved the plant to a more shady position and repotted in fresh ericaceous soil. Is this enough to help it recover or should I do some other things?
Thanks