I've been wondering the same thing. I'm no medic at all, but perhaps a good starting point would be to list the things you would be more likely to suffer from on a Northern Europe Bushy trip...
(In no particular order)..
1: Minor Cuts
2: Major flesh wounds
3: Eye injury (sparks, dust etc)
4: Ankle Sprain
12: Insect Bite / Pest infestation (Tick)
14: Chapped Lips
15: Food Poisoning
Oh, and not to forget the most likely of all..
What else? A small first aid kit can't cover every eventuality.
"When it rains, we get a little wet, and when the sun shines, we get a little hot"