Hi...I've taken 9 months of my maternity leave on December 17th 2018 but want to extend it to the full year. I'm aware that the last three months are unpaid. I have already said to work I will come back on the 17th December on reduced hours, this has been put on writing. I am wondering if I now tell them I wish to extend it by another three months (so won't be retiring untill around mid March 2019) can they say no or do they have to legally honer me the time? How much notice do I need to give them to let them know this is what I wish to do? I am due back in roughly 8 weeks. Thank you