Help trying to display compass reading onto 16x2 Lcd

Actually, this is incorrect.

That is correct, there are three, but the first overload will be used.

I cant seem to get the Lcd to display the heading. Has anyone got any pointers.

OK, it seems that all pointers given are not understood well enough,

Have you tried printing the variable headingDegrees directly?

void Output(float headingDegrees)
{
  Serial.print(headingDegrees);
  Serial.println(" Degrees   \t");
  lcd.write(headingDegrees); //<<<<<<<<<<<<<<
}

Note: you cannot read back from serial what you wrote to it unless there is an echo app on the other site