Here we use MediaNav with iPhone4s, 5, and 5s. I use spotify to stream music, it works great. But each approx. 15s the signal drops for a moment.
I believe there is nothing wrong with the bluetooth connection of the iPhones, as I use them with other audio systems.
The link belows shows the following stated:
"There is a fault with the MediaNav Bluetooth connection when streaming music."
"Renault are aware of the fault and will not be telling any new customers"
"It is not a priority"
"There is no timescale for a fix"
http://www.shesaidbeauty.com/sammakeup/blog/renault-clio-medianav-bluetooth-faul t-830095