If I were driving I'd do the M23 M25 & M3 takes you out the way a bit but is continues motorway driving, I'd leave earlier myself to avoid any traffic and get to Yeovil for Breakfast :-)
Oh wise people of NSC which route would you take to Yeovil ? ( from Shoreham )
3 hour drive - you should get there around 1pm
Coach probably take about 4 hours with service station stop so probably make Yeovil around the same time 1pm