My sister-in-law went on maternity leave two weeks into September. She has been told that she has been successfully moved up the pay scale as a result of her PM 2017-18 and that this should be backdated to September 2018. Will this affect how her maternity pay is calculated? Could someone direct me to where to look to help her? The burgundy book does not seem to outline exactly what period the pay is calculated on, or I looking in totally the wrong place!