SG 279a 1/2d Very Pale Bluish Green M4 (-) marginal scarcer unlisted shade marginal in Post Office fresh unmounted mint condition with bend affecting selvedge only and well clear of actual stamp. This is one of the many shades that have previously seen Hendon certificate issued for though with no reference to or inclusion in any of his previous publications lists.

A quick check on my freely available reference spreadsheets shows no fewer than seven such shades on the halfpenny value alone.