My personal view, shared by a lot of Labour people is that David Davis is doing nothing more thatn playing an attention seeking game. H&H is a safe Tory seat with and despite attempts to turn it into a debate on Liberty, it will be used by voters as another chance to give Labour a bloody nose.
David Davis knows this, and this is why the whole thing is just a pointless stunt. A victory for David Davis against Labour will be used relentlessly against the government. David Davis is putting nothing on the line here, he just wants a chance to pretend he's Benjamin Franklin for a bit. He's a man or opportunism, not a man of principle.