only use large margin on hero banner on desktop
apply styles to hero banner elements on mobile as well

The basic styling of these was mistakenly inside @media rules so weren't
being applied on mobile screens
swap around order of hero banner elements for display on mobile

Move the constituency and party to second to display as then we can
display them under the MP name on a mobile screen.
Then use CSS to swap the order in which the search and action buttons
appear on a mobile screen
remove size from mp speech search box

we want this to be controled in CSS so media queries work correctly