Desktop & Mobile Theme. Problem with displaying different homepage

Hi guys and girls,

having a bit of a bummer of an issue…I have 2 themes. One is a desktop theme and looks great on tablets and desktops but on mobiles it looks naff even with responsive design in place. Thats why i designed a separate entity that will work well for smart phones.

I’ve tried adding the little bit of code to functions.php for the desktop theme which is : –

$home = get_page_by_title( ‘home’ );
update_option( ‘page_on_front’, $home->ID );
update_option( ‘show_on_front’, ‘page’ );

and this to the mobile theme functions.php : –

update_option( ‘show_on_front’, ‘posts ‘ );
?>

I then installed and tried a couple of plugins. First one is Device Theme Switcher & the other was Any Mobile Theme Switcher, the 2nd one I thought had cracked it but then a colleague visited the site via the desktop and it showed the mobile site when the desktop site should have been displayed…

…if there is anyone out there that knows what is going wrong , pleeeeease help.

Would it be worth having a sub domain for the mobile site that redirects anyone accessing via a smart phone to that url? Is that one of the easiest options without touching much of the php?

muchas gracias in advance