PS - if you DO get a moment spare, Kilmory Oib is worth a visit:
http://www.ancient-scotland.co.uk/site.php?a=99
http://www.kilmartin.org/kilmartin/sites/ch8.html
Slightly off-topic, I guess, cos there you'll find a medieval(?) village, engraved cross slab and holy well. Only a short drive from Kilmartin itself.
G x