i have a camelia that always flowers well but the buds +flowers turn a horrible brown around the edges and spoil the appearance

Camellia flowers do start to acquire unpleasant looking brown blotches on the petals within a very short time of opening up. If the buds going brown before they even open, that's a different problem - you don't say when your Camellia flowers (some are really early, some later) but being south facing, it may be that, when the sun comes up and hits the buds, they're damp, and they might be scorching because of that.
As regards browning of the open flowers, it's not so noticeable on the red varieties.