Had full bloods done. liver & thyroid fine. everything was perfect apart from slightly low neutrophils. should i be worried?

Probably not: 5% of people are out of the normal range on any lab test, so if you have 20 tests the average person has one thing out of range! slightly low neutrophils are seldom significant. This is a test that can change day to day so on another day it might be fine. But lab tests don't give a complete picture; some with thyroid or liver problems have "normal tests." perfect tests don't mean perfect health!

Thanks for asking!: Slightly low neutrophils are not specific. Follow up with whoever ordered those tests please.