Scanning the seawater, I noticed a white fronted diver like bird approximately 50meters off shore. First impression was a moderately-sized diver with medium heavy neck that had no noticeable dark collar. Red-throated Diver? I am very familiar with winter RTD's and this just didn't give off the right jizz. The bill was medium sized and disappeared into sea as the colour was the same. Through the scope, the head was quite rounded without the steep big forehead of Great Northern Diver, but not flatish like RTD. The bill seemed small at times. Dark grey extended from the bill over the head down to just meet below the eye, white cheek patch, then the dark grey extended down the back of the neck. The demarcation with the white front of neck was clear. The dark grey was uniform in colour with clear edges. The front of the breast bulged and was all white. The mantle/back was dark and pale markings seemed to be present at certain angles. All along the flanks a white edge showed with slightly more above the legs. However, it did not show a clear white patch on its own. Always the white lateral stripe - the bird did seem to be carrying its self high in the water without any attempts at diving. In hope more than reality, I did scrutinise the size of the bill and indeed, any views of the underside of the throat. Thinking to exclude Pacific Diver. There was no strong dark chinstrap, but occasionally a smudge under the throat could be seen but possibly shadow. There were no other divers present to compare bill size. As I said, it did seem small at times, but as it also 'disappeared' into the sea I decided this couldn't be objectively assessed further. As we watched the bird continued to drift further away. Another birder visited later that day, but the bird was not to be found.