Well, I got fed up with it and raised a support case with Jolla. Symptoms were that when using BT and WLAN to stream internet radio (TuneIn App) to headphones I'd get the WLAN dropping the connection. It was inconsistent with no pattern.

They've inspected in and found no fault. Their comments were that the BT and WLAN are on the same chip and when both are working together then it can/will get overloaded. However, if it works fine sometimes with no disconnections then there is an intermittent issue is there not!?

Since its return the BT settings have been totally lost (not sure if this is cached on the BT Module or elsewhere) and the issue still remains. Guess I'll either need some wired headphones or a different phone.

My N9 is pretty much dead now. I dropped it and it frequently has no reception. GPS is also intermittent. Shame as it was a 64GB one!