Beater
It really is nonsense to think you need to be VMC up to MSA on a departure before going IFR I'm afraid. Of course you need to be sure of obstacles and know your surroundings before going IMC and a pilot must be aware of local obstructions and terrain before doing so. This area was about as flat as you can get, with nothing above 200ft I shouldn't think. Now if the location was somewhere hilly/moutainous be a different deal.
And also agree ShyTorque on the nightsun - it was almost certainly bumbling into patchy mist/fog at low level that caused the disorientation and LOC and with the amount of moisture in the air the glare would have just made things a lot worse. Scant ground lighting is a nightmare - a few bits can mislead into thinking vis is better than it is, then when there's none you're effectively IMC. It was probably recognition of the well lit truck yard that sucked Steve into thinking (a) he was nearly there, and (b) the vis was going to be better than it was over the last mile or two. Once that had gone.... Tragic lesson for us all.
Sadly this was not unlike a B206 accident near Goodwood many years ago. Someone will remember the details - although in that case it was trying to sneak over the South Downs that was the final problem.