In the States we have a standard 4 year/50,000 mile warranty that includes maintenance items. Surprised to hear the dealer is charging you since it appears you're still within the limits of this?
Just a girl and her 863 ponies...
2013 Santorini M3, 2016 328i Alpine White Wagon (Lab hauler), 199x Sapphire M3 (because racecar)
///M-Flight Western US Regional Manager