Self-employed author - HB capital & income

I have a client who is a children’s author and has earnings from writing children’s books, and providing occasional educational workshops. She usually gets lump sum payments, such as advances or contractual payments, and the workshop payments are often paid in large sums at the end of a run of sessions. The client’s income is quite sporadic, and insecure, so she seems to hold onto the monies as security. As per self-employed rules her income is calculated on the previous year’s accounts (only c £9k for last accounts). The issue is with the treatment of the lump sums payments. These go into her bank account/s, and the council have told her to report monies in accounts that take her over the lower capital limit. I cannot see anything in the regs or guidance to show that the payments - effectively income - should not/cannot be treated as capital. But it does seem like both S/E income is being counted and tariff income from the capital generated by that income.

I would welcome any advice/thoughts that might help.

Thanks in advance