Row spacing issue with WP gallery

Hi,

Im having an issue with some spacing of my wordpress gallery of images inside a page.
https://www.mlasa.co.za/gala-dinner-2010-images/

They all display and work fine, and no the lightbox hasn’t messed it up slightly. It works the same without it on.
Also if I specify the number of columns it doesn’t change the huge gap, but it does work and specify the column number… which is great.

Not sure why there is such a huge break under the first line of images?
Any ideas would be much appreciated.