Deferred entry

I'm applying to university through deferred entry, so I will start in swptember 2018. However I'm a bit confused about when I apply for student finance? Should I do it now or wait? And if so how long?
Thanks in advance

You apply in the Spring before your course starts.

If there's even the smallest chance that you might start in Autumn 2017 then it's worth applying this Spring - it's easy to cancel an application for a year but applying late can cause problems and delays in getting you and your university paid.