Nerfherder said:

Could the PAL version be sharpened slightly, without introducing halos like the US capture?

That's a good question. But I think you would get even better results if you tried to reduce the halos on the US without making it too soft, take the first cap for example, where the details in the walls above the doorways are completely gone in the UK transfer, you can also see the sligthly clipped white levels on the lights above the robot.

I don't know, I guess we will have to experiment and test to see what is getting us the best results. Fortunately we have a lot to work with, thanks to you and Silver. :)