Spaces between WP blocks since update

Hi, I've just updated my theme to 1.8.1 and I now have spaces between blocks on my front page... http://www.shechameleon.co.uk There is a big space above the main Youtube video and also between each of the three YouTube videos towards the bottom of the page. If you refresh the page you'll see that the YouTube video briefly displays in the correct place and then moves down. There are no empty blocks above the YouTube block - I've tried deleting the block and re-adding to the page but I get the same result. I am using a child theme but I get the same result if I activate the parent theme. Any help with this would be great. Thanks, Darren