If you have a child that is 3 before 31st August 2017 (or 4 and not going into Reception) and you want to apply for the extra 15 hours childcare for use between 01/09/17 and 31/12/17 there is only 5 weeks left before the deadline (31/08/17).
Applications after 31/8/17 won't be entitled to the additional hours until 01/01/18
apply here - childcare-support.tax.service.gov.uk/
www.thestar.co.uk/news/don-t-miss-free-childcare-deadline-sheffield-parents-warned-1-8618044
FAQs - www.sheffielddirectory.org.uk/kb5/sheffield/directory/advice.page?id=_dg8Dvgg5Zc