BMW F650GS 2010 - Major Service

In about 4 weeks I'm taking my GS on a pretty tough one week trip across mountain ranges, bush etc.
I thought it would be good to give the bike a decent service. I bought the bike not long ago and I didn't bother with the service as it has everything up to date all done by the dealership. Happy I did, I have learned a lot and some things (ie. spark plugs) really looked pretty bad.
Note: The rubber seal was in fact on the filter - it must have stayed stuck to the engine when I was taking it off. Make sure you lubricate it with engine oil before you screw it back on.