A question about EPC

Other

I am making an enquiry for a relative. She entered into a rental agreement in February 2012 but the landlord (who are Trustees of the estate where she rents the property in West Sussex) did not provide an EPC at the start of the tenancy and have to date not provided one and it is understood have in deed not done an EPC.
There is an issue with very high electricity/heating bills which she is now expected to pay. The high bills have come as a shock as there was no indication that electric convector heating would prove to be very costly. The property is a period Manor house and is poorly insulated, has very high ceilings and has single glaze windows. The electricity company prompted for readings annually and it became very evident to them that she was not paying enough on a monthly basis and are demanding an arrear bill of £2000.00.
Can you advise if The Trustees have acted within the law or not? And if they have not, is there any action she can take against the Trustees?
many thanks
Ralph Cowan