Padding in Datatable Header Cells

Hi,

I am trying to reduce the amount of padding around the cells in the datatable header. So currently I have: http://imgur.com/a/vRn6k and you can see that there is padding on the left hand side.

Now I have looked at webix_ss_header in the css and that has no padding so not sure why there is this space? Tried different alignments also with no effect.

Thanks

Gary