What exactly is a "unique" hockey stick? Who signed it? There are so many variables that it is impossible to give a value based on the vague information you have provided.
in my opinion i would say about £1000
It is worth somewhere around $200-$400.
Michael Lee - field hockey - was born in 1980.
Michael Boyce - field hockey - was born in 1980.
Richard Norris - field hockey - died in 1980.
ESPN National Hockey Night was created in 1980.
Kate Walsh - field hockey - was born in 1980.
Philadelphia Firebirds - ice hockey - ended in 1980.
It was an open tryout
Finland
As with all things that you would like to sell, it's value is with what your buyer is willing to pay.