Flights from BA are approx £90-100 pounds per person from manchester to Dusseldorf. Cheapest Ive found so far. For 3 of us planning on going it is cheaper (just) to fly than drive, but have not looked at how much the hire car/van is.

If there are 30 people going then I would have thought that a coach would be best. It could start with rodger and works its way down picking people up on the way. If theres any interest in this I can look into it further.