External GPS for iPhone

Hi There! There are still a lot of iPhone 3 Gs out there, and especially their owners might be unhappy about the GPS accuracy. They can be helped with an external (Bluetooth) GPS receiver such as this one: http://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=GPS+iPhone&x=0&y=0 or: http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=iPhone+GPS&x=0&y=0 However, I own a Holux M-1000 which I had purchased to use with a NOKIA phone. I was quite happy with this device and would be happy to use it with my 3 Gs. I thought that the iOS blocks external Bluetooth devices or decides which device the iPhone is allowed to pair with. accessibility@apple.com, however, tol me that it is down to the manufacturer of the Bluetooth device to make it accessible for the iPhone. I wrote an e-mail to Holux customer support and received the following answer: "Hello." Have a nice day. Sorry, Holux GPS receiver is not compatible with Apple series product. We ever tested." Aah, right. Is anyone interested in a Holux M-1000, used, good condition?