Hi all,
Just to say that I received my drone yesterday good news is that the ultrasonic issue is now fixed and as we suspected, this was definitely a hardware fault. The ultrasonic pulses can be clearly heard, even without a microphone.
The bad news, is as I suspected would happen, the image just isn't quite as sharp. Comparing RAW files taken with both old and new devices, the new drone lens is clearly more astigmatic towards the right of the frame. At this point, I'm not sure whether I have the time or energy to send it back or to just keep it, as it's a gamble as to whether I'll receive something that's better or worse.
Cheers,
Mark.