Well, the X34P has arrived and I've set it up. I'm happy with it for the price I paid. I have the usual bottom left back light bleed that most people get, but honestly I've tried a few games and its barely noticeable in use, you only see it during bleed tests. I was going to take a photo, but the camera on my phone makes it look 1000% worse than it is. The photo even shows significant bleed in the top right, which I'm just not seeing myself, it looks fine there. I think if I'd paid the full £1000 I might be tempted to send it back due to the bottom left, but I think I'd only get sent more of the same, or worse, so for the £680 I paid I'm going to hold onto it and play around with some of the settings.
The 1440p over my old 1080p ultrawide is very impressive though, massive improvement when gaming, although now my frames have dropped from 90 to around 60, which will inevitably lead to a new GPU at some point......