Hi Mate,
Firebird (Steve) is the know it all on dp stuff really.
http://www.dpfirebird.co.uk his is your best bet. It depends alot on which model it is, What condition it is in, what the stamped number it is and at the end of the day the demand for it. If nobody is particulaly after one it wont fetch much but if you get 2 people after 1 then they will bid the price way up.
Probably best for a price if you post a picture and a breif description of where it came from so people can offer a guide