code 489l means the first 4890 you earn in the year is tax free
then they have a calculation like the next 3k 10% and the rest at 22% etc
it is an good idea to send over your p60 to your tax office normally it is printed in your payslip or payroll people know where it is they do take upto three years back p60 they will do the calculations and if they find you have paid more tax(
)
they will refund you
the above figures are ball park i could be out by a k or less
cheers
p.s. if your wages vary month to month there is a good reason you might have paid more tax then normal so it is a good idea to send in your p60s to inland rev