There is a large white arrow clearly visible on Google Earth just to the east of Skipness village (by the graveyard) at the top end of the Mull of Kintyre. I believe this is a hangover from WW11 and was something to do with a nearby weapons range. In addition, I think there is another one further south, not so easily seen.
Just found the second arrow. It’s just south of the village of Crossaig, in scrubby land east of the B842.