I almost didn't go today due to the strong southerly winds, but this proved to be a benefit as the bird was restricting itself to the sheltered side of the hedge near the entrance to the marina.
I picked it up on song, but it took me a minute or two to sort out the direction it was coming from. I tracked it down and luckily it was showing continually. At times it was really strikingly pale and then the light would change or the background and it would appear browner. Close inspection showed yellowy green on the edge of the wing and the outer tail feathers. Otherwise it was pale especially on the underparts. The supercilium lacked any yellow tones .
I managed to record its song and create a short video on You Tube.