I have got it, Jack has got a minimum wage job at her own company, on a bootstrap limited. She interviewed herself and was the best (and only) candidate for the job.
Jack's new role is as a replacement for Caroline's hands!
Jack is also making the most of the UC to top up her wages by working the bare minimum she can get away with before it affects her benefits. She's been watching old re runs of Bread to get some pointers. (No matter it is 30 years out of date, most of her information is no longer relevant)