@McrNick is spot on, main dealers big kick is the hourly rate, my local I think is at >£100 now!
And, as @ND12 said, certain aspects are not age dependent but mileage however dealers just lump everything in together. The 6th service, if also doing the estimated annual of 12.5k, would require spark plugs but as you are not close to that I don’t see the requirement.
I did have previously shared this screenshot of a price breakdown for services on NDs:
Prices may be marginally out of date
I am curious how they have reached £625 when, even with spark plugs and a £100/hour labour rate it should only be ~£410!
It is also worth reading the First Service at Main Dealer and the 30AE 4th service threads for more information.