Gerrof, this isn't a LARP game. There are no character cards, no rolling of dice, no power ups, no magic potions and no spells. You won't be sitting around in huts trading tokens with one another or pretending to have drunken brawls. And there isn't a script. 
For sure you can invent a character for yourself if you wish. Many players already to this (I will be personally reprising my Captain Mainwaring impression, last seen at the Horn game) and it does get you in the zone. If you could categorise this event then perhaps you might call it airsoft reenacting, not make-believe 'filmsim'. This was a real event, a huge story in it's day, and as much an embarrassment for the authorities as anything. It will certainly be realistic - no crazy slaughter of human life, indeed a respect for life is the order of the day. It isn't a battle zone, it's rural Britain - and the reality is, then as now, if someone points a gun at you, you put your hands up. And it gives everyone, regardless of fitness (no hills!), weaponry or kit level a chance to play WW2 airsoft.
Bicycles welcome!
