If you have a Arduino MEGA connect the SCL and SDA pins to 20 and 21.
Do not use Analogue pins 4 and 5.
This is just in case there is anyone else out there wondering why there comms isn´t working when the circuit and software is correct.
There must be another idiot like me??? wasted an hour on that.
The info on this thread is fantastic I would like to thank everyone who posted as it saved me a lot of time.