I will update this post with some links etc but wanted to get the images up quickly.
As we returned from our dog walk this morning I heard the distinctive 'Drrt-drrt' call (sometimes called the "old telephone call") of a Red-capped Robin. On gathering my binoculars and camera and returning to the site I soon spotted an adult female of the species.
She stopped calling and flew into another tree from which she chased another very similar bird. I was able to locate the other bird and here are a couple of images. Although it didn't call, and it doesn't have the red forehead, I believe this to be a second female (possibly a younger bird).