for me i'm more interested on where its been serviced.
i don't trust nissan garages as they are only good with micras etc, they don't tend to know the zed that well, and the ones that do are few and far between.
i use TEAM AFM to do all work and servicing on my car, they tune and prep BTCC touring cars and other sports vehicles and know their vehicles inside out.
i think those stamps in my log book are far more valuable than the nissan ones.
at the end of the day, servicing isn't a major job. if you know your way round a car you can't go far wrong. as long as its been serviced and had correct consumables used thats all i'd want to see.