Perhaps, if they hadn't invaded Belgium, then Britation likely would have come down on Germany's side. As to resistance movements etc, there have always been gurrillas, even in ancient Rome.

Had they been benevolent rulers, had UK and hence Commonwealth support then yes. They could have done it, at least Europe.

Think on this, there have really been three world wars already and the UK has always been on the winning side. The reasons? Money, Naval Power and being safe on a island.

In WWI Germany was facing Italy, Belgium, France, Russia, the UK and her Commonwealth all at once. They still held out for four years. The UK brought most of the troops, without them the French would have been outflanked and out thought.