Continuous Line as an Attacker?

[Bacillus98]

As an attacker, is it best to spread out your forces or break down a few battalions to cover your flanks while attacking? Here's is a pictorial example using Sea Lion '40 game:


It's not letting me inserting image correctly so here's a direct link: http://imageshack.us/photo/my-images/213...acbmp.png/

The German divisions are in snake like columns in T-mode heading towards the defensive British line. If I keep the attackers grouped up for assaulting key sections of the lines I leave my flanks exposed for the British opponent to sneak units in the rear line. If I spread out my attacking forces to cover flanks I risk diluting combat power. As a player, how do you guys decide on this matter?