Not sure what settings you used for video resolution but your upload to youtube is only 720P. It could be still rendering as youtube is slow that way sometimes. If its only 720p then your not going to get great quality
I would shoot 1080p50 to start with. Use Sunrise/Sunset as a fixed colour balance - make sure you are in manual not AWB mode. You will need an ND8 filter that allows 100th second shutter and ISO100. I am on the other side of the channel - Cardiff - and this works for me.
There is a very good YT video of Typhoon camera settings for the Q500 and the H by Frank someone Photography?