In general tipping is not required in Europe to the same extend as it is in the US.
Thus not to tip would be absolutely okay. If the driver or guide is the owner and thus gets paid directly by you anyway, you even should not tip.
If they are employees, European laws guarantee fair wages without tipping. Nevertheless it would be a nice gesture to give a token of appreciation such like € 10 or maybe 20 for each driver and guide if they indeed were great and are ready to accept any.