Well, booked it in for its 6yr service today. Dealer was absolutely un-moveable on the "Honda" £255 price which includes air & pollen filter and brake fluid change. MOT for £35 though.
They said the plugs ought to be done, although I see that as 75k mile specific item, so I refused those. Also manual gearbox oil change is 8yrs (although that seems to vary depending on where you look) so no issue there. Coolant 10yrs.
The one item I hadn't considered was fuel filter. Again dealer said it ought to be changed at 6yrs at cost of £120. I know on the Mitsubishi Colt we just got rid of it was an 8yr thing and very expensive as it's integral with the fuel pump. Frustrated owners who bought replacements reported that the old filter was as clean as the new one! So I declined that too.
I asked if the Honda Assistance would still be renewed and they said yes.
Interesting that they had no issues doing the work on Monday - ie next working day.