Hi Trust Links,
There is no easement regarding overpayments due to official error with Universal Credit as there is with Legacy Benefits. So if at the time the ESA would have been deducted from the UC then a lump sum which is made up of backdated ESA would need to be taken into account. This means that you need to be prepared to repay some of the lump sum to the DWP. But you will be entitled to the additional payment of the UC LCWRA element.
David
Nothing on this board constitutes legal advice - always consult a professional about specific problems