If someone who was on maternity leave had a 2nd baby before before returning to work and therefore went on a 2nd consecutive maternity, would her 90% of pay be based on original salary or 90% of last years monthly maternity pay.?
The average earnings is based on the pay received and averaged over a period of at least 8 weeks up to and including the last pay day before the end of the Qualifying Week (QW) and the QW is the fifteenth week before the Expected Week of Childbirth (EWC.)
In the example you gave, the pay would be the SMP so it would be 90% of that figure