Thanks Brian!
Yes, Ballochmyle is the site of the "Ringed Stars" or Sun-Flower-like carvings.
They are also found -in a smaller version- at Poltalloch (Argyll & Bute).
There are at least three of these motifs at Ballochmyle in different variations: http://rockartuk.fotopic.net/p57301445.html
They are more common in the Passage Grave Art of Ireland.
Thanks to George for pulling the right piece of turf!
Cheers,
Jan