HDR-AS30V won't connect to PM on iPhone 5 iOS 7.1

[thecasper2]

I have just bought a HDR-AS30V action camera and have downloaded the latest Play Memories app (v 4.2.3) on my iPhone 5 (original 5) running iOS 7.1.

The wifi connects correctly (DHCP too) to the camera. However when I run the app, it either stays on "Searching device..." indefinitely, or eventually fails saying "Comminucation with the shooting device failed".

I have installed Play Memories on a family member's iPad 2 (also running iOS 7.1 I believe, certainly at least iOS 7). and the camera connects immediately.

I have followed all other troubleshooting tips I've seen so far: resetting the camera, formatting the SD card, reinstalling the app, powering off my iPhone. All of this was to no avail.

What can I do to get the connectiong working?

Thanks