Hi Delphi11
You sister should send a Journal message to the Work Coach stating that she gives you " explicit consent " to speak to the Jobcentre Work Coach about the New Style ESA. You can then take the phone call. Before the call ask your sister if she has written down the UC memorable information that the Work Coach may ask about and use as an excuse to be difficult.
David
Nothing on this board constitutes legal advice - always consult a professional about specific problems