£30.000
It's worth exactly one pound.
A 1889 gold 5 pound coin is worth 5 pounds of gold, while a 1889 2 pound gold coin is only worth 2 pounds of gold.
Such a coin does not exist. The English have never produced a 4 Pound coin.
Face value.
£25
8-11p
£2
About $300
I suggest you get a good coin book and search for your coin in there.
The Tercentenary of the Bill of Rights 2 pound coin sells for between $4.50 and $7. The Tercentenary of Claim of Right 2 pound coin sells for $9 to $10. These are the prices they sell for on auctions sites.
As I type this the value of 1 pound of gold is $18,040.00
An Irish "Millennium" coin, with a face value of one Irish punt (or "pound"), is worth about US$7.50 in Uncirculated condition and about US$8.50 in Proof.