In reply to iangpark:
From RB Frere's article in SMCJ, 26/137(April 1946), p355. Incidentally the same one in which he reports his first ascent of the rather better known Savage Slit.
"Here are one or two notes regarding the curious rock formation, known as the Clach Bun Rudhtair on Ben Avon. The pinnacles run north to south. The first and third are easily ascended by at least two routes each. The central pinnacle is divided by a deep crack; rocks falling into this crack have formed a window, mentioned in the “S.M.C. Cairngorm Guidebook.” The part of the pinnacle lying to the north of the crack can be climbed by an easy chimney on its north side; or by a narrow and strenuous fissure on its northwestern aspect. That part to the south of the crack can be ascended by a through-route in the top of the window followed by a short traverse to the right. Interesting scrambling can be found in the group of rocks. I note that the “Guide” mentions that one of the rocks had had no recorded ascent. This must refer to the central pinnacle, since the other two are very readily ascended. K. A. Robertson and I climbed it yesterday (7th April 1946)."