"I was very interested to read Dr. Urwick Is study of this flaw. The following notes may be of some interest:
I have a complete pane of the 2d dull green (S.G.20) without slash flaw or irregularity in the solid band and all the plate numbers are normal. A corner block in deep green also shows no flaw or irregularity. Two complete panes of 60 of the 4d grey (S.G. 22) show no slash flaw but have damaged frames. In both panes the bottom plate numbers are damaged there being a horizontal white mark to the left of figure 1. There is also a small figure 2 in the margin under the fourth stamp of the bottom row. I have also a block of six (3 x 2) in a pale shade without plate flaw but damaged frame. In this case the inner white line is also damaged and the solid colour appears to be disturbed suggesting the removal of the flaw. A block of the 21/2d on 4d grey (S.G.31) shows no flaw or irregularity. The earliest example of the 'slash flaw' I have in my collection is on the 21/2d ultramarine (S.G.17) which is dated 17.10.1894 and the latest on. the 1d carmine (S.G.21) dated 21.7.1897."