Q.Why is my Camellia Sasanqua browning and dying off
I have a hedge of Camellia Sasanqua and throughout there is certain growth that is browning and dying off. Whilst there is a small scattering of this throughout the hedge, it is quite prominent at one end in 3 of the plants. I have seen the hedge being surnburnt in the past and this is very different to that, as the leaves and stem just die off. Thank you in anticipation.

Your images do appear to be a sun scald on your Camellia.
My suspicion is a fungus may also be the cause. The way that you describe more damage to one end of the hedge, then moving through the plant makes me come to this conclusion. I had a similar event in my garden a few years ago, though on a different type of hedge.
Here is an article that has more information.