They are catalogued, among other places, in Barefoot's Commonwealth Revenues.
Ceylon looks to be 1872, Stamp Duty #5
COGH looks to be 1878/1880 if watermark Crown CC, and 1885 if watermarked Anchor.
COGH is minimum CV either way. Ceylon is slightly better, but still nominal value. I like them, though, and I tend to buy some when I see them. Here in the middle U.S., dealers rarely have them, but when they do, almost none of them have been catalogued, so they're either the basic "25 cents per revenue" or the default "$1" that is often the going price when the dealer has no idea what he has.
ETA: Crown CC would be #85 and Anchor would be #112. (Corrections always welcomed.) Source is Barefoot 10th ed.