It being the first I've spotted for sale in 40+ years, and having been missed by the seller (though surely bloody obvious?), I'm very pleased to have acquired this C over L 1673 farthing. Although I have read fewer than ten are known I have seen two only, those being the Colin Cooke coin and Joe Lee's, both of which are inferior to this one which I'd grade as a solid good fine. There are no online records of any other examples, be that sales or in collections. I also checked through my old farthing catalogues and found no examples listed for sale, or even as a recognised variety, at any point throughout the 1980s and 1990s.
Fifty quid. Bargain.