Large family and UC advance under half of monthly needs

Any thoughts please.

Family of one parent, eleven children, one child severely disabled.

UC claim owing to natural migration’. No money for 2 more weeks.

£1500 UC advance made, which is less than half of monthly needs.

DWP argue that repayability is the issue, as the advance should be repaid at up to 40% of the standard allowance for maximum 12 months.

My line is that the repayment rate is actually 15% in the Regs and that the 12 month repayment period is guidance not law and DWP can extend. This seems like a very good case for some flexibility to be applied.

Replying to my own post - the posts by Charles and HB Anorak at the end of this discussion-  https://www.rightsnet.org.uk/forums/viewthread/14437/#71177
- dish my 15% argument and it looks as if DWP can dispose as it wishes. Not good for a large family to have repayability promoted over avoiding hardship but it looks as if effective arguments may be thin on the ground..