10 Or 10A.... That Is The Question!

Why would you assume those years?

Isn't that the date that # 11 were used?

As mentioned earlier the stamps is an 11A. Scott specialized shows years of printing as 1853-1855. It could also be later.

Thanks stallzer, that's how I came up with the date, its just so I know where to place it in my cover album,
Its a shame I don't know more about postmark or cancel, that may narrow it down a bit...
Cheers and thanks everyone for your assistance,
What I have so far is 11A circa 1854 onwards.
The colour still has me a bit baffled, I'll have to check out my specialized for variations in colour if its in there at all.
Cheers

Here is a "as described" 10A orange brown I recently picked up at an auction. Still need to verify the auction description is correct but you can see the difference between this one and yours.

Its a lot sharper isn't it?

Stallzer, your stamp looks like plate position 9R2e or 2L if it's not Orange Brown.

Here is 9R2e