So, final update from me on this thread. It arrived yesterday and after about 3 hours of charging, firmware updating, imu calibration and general checking I took it out for its first gentle flight. Beginner mode on, I flew for about 17 minutes at a local running track. It was great, I'm really happy. I'm glad I've spent time practicing on the Syma X5C because the P3S is so easy in comparison and I feel confident with the controls.
Thanks for all the advice and support - I'm especially pleased I started in beginner mode as it would've been very tempting to fly too far & high on my first time. I think I'll turn it off next flight and slowly increase the limits manually using the app settings over the next few flights.
I'm absolutely delighted that I've finally got a Phantom after the years of dreaming and I'm looking forward to many hours of flying and aerial photography from now on.