Judy
You don't say why you have lost your ESA(IR) payments but on the assumption that this is not likely to change in the near future then you do not need to inform the DWP of the lump sum, ESA(CB) is not affected by your savings.
The monthly payments are a little trickier. ESA(CB) is reduced by pension income in excess of £85/week, you are under this limit but I feel uncomfortable saying you do not need to contact them about it although I think it likely that they will not be bothered if you do not let them know at the moment.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
