Ahh, the near mythical C-series wrenches!
I've got a set of AF ones from 3/8" to 3/4", and a part set of metrics (if anyone has 16,17,18,19mm they'd like to sell?)
The logo puts them in the late 1960s to mid 1970's. I am told they were an effort by Britool to make something shinier than Snap On.
Apparently the best RJ series forgings were selected from the production line before being stamped with this logo and hand polished to a mirror finish whereas standard RJ series spanners have a satin chrome finish on the shank. Because they were hand done they were very expensive and few were sold. They certainly do not turn up very often on Ebay, so the rarity part is true.
Having compered the two I don't think they are the same forgings as the RJ combination spanners. The style is very similar to the RJ, but the lengths are slightly different. EDIT changed my mind on that, see later post.
Some of the 2RB ring spanners have a mirror finish and this logo on as well, so it was obviously intended to be a new range for some reason - perhaps a false start at the later Automotive range which had a full polish finish and also used part numbers starting with a C.
Anthony