Chevrons, variation and wear

A chevron shape (^) can be a useful identifier on a number of moths.  Probably the most common moth with this shape at the moment is the tiny micro Blastobasis adustella, but due to variation and/or wear this can be difficult to see:

A few days ago I was momentarily nonplussed to see the following macro-moth with a central chevron:

but closer examination showed at one end was a whitish round mark; i.e., this was a White-point or Clay. Looking at further examples of the Clay, and sometimes of the White-point, one can often see this chevron shape at least faintly (it is effectively the proximal edge of the kidney mark).  When seen on the White-point it is very faint and usually slightly lighter than the ground colour (reddish-brown), while on the Clay it is often a pale cream colour and stands out more (see also below). Indeed the illustration by Richard Lewington in the Waring & Townsend field guide shows a pale area adjacent to the white spot for the Clay, but not for the White-point. The Clay is reputedly more variable in colour, and may be pale as in this case, but the white spot is usually small and/or tear-drop shaped.  However, to me the overall size and shape, as well as the shape of the white spot, etc. make this 'chevron' specimen more like the White-point than the Clay - so is this another case of variation and/or wear making identification difficult?

John Thacker, Harwell