Paid SMP in lump Sum

[catkin1508]

Just a quick question i was paid my full SMP and redundancy in March. However the SMP is to cover this tax year so unsure if i have paid too much tax?? How do i find out?? I have taken the full 39 weeks as i am not planning on working during this period. Sadly my work paid me in March and the new tax year started on April 5th- how do i find out as well that my NI stamp has been paid for these 39 weeks if the new tax year has started???