Again Awesome Work Mate,
.wav definately saved to the .gpi but will not play on gps. After saving to .gpi I noticed that the file I used (Testing 2.wav) was now accompanied by a new file called Testing 2_epe.wav in the same folder. Its a duplicate file with a different name. I got the bmp working. Not sure if it will help or not but whilst playing with GPI_Viewer I noticed that in the garmin poi's they are marked as .wav format with .tmp extension
Thanks for all the work