I was in the area and stayed one night Arinagour couple weeks back.
Noticed the moorings, and remembered this thread, but only just remembered to add my bit.
The moorings look in good condition from the surface, as if quite new.
But in my opinion they are too far north.
Considering to pick one up and use it for the night, accepting that I'd have to pay (I don't mind paying, it costs someone something), I motored over to one, but thought the most inshore one would perhaps avoid the worst of that unfortunate swell that always seems to come in there. But it was in such shallow water, there was no way it was useable. It was bout 1/4 tide, ebbing. Using the inner three moorings would have meant being on the rocks at low tide, and we don't draw that much, not a deep keel!
The inner 2 had no pickup buoy.
The outer 4 had buoys, but by this time I'd decided that their positioning was no good and I decided to anchor.
Another boat came in, sniffed round the moorings, then decided to anchor also.
Then a 3rd boat came in, attempted to pick up a buoy, failed several times, tried for another, failed again. I don't know why they failed to pickup, but they too eventually decided to anchor.
So that night, (14th Aug I think), there were three yachts anchored, just in what I'd describe as the "right" place to anchor in Arinagour, and 6 unused moorings.
"Contender" Rival 32: Rhu and elsewhere.