When it comes to registering your title, the lawyer could do it by designing you as Gillian Chapman, otherwise Gill***** *****dley. An affidavit by you explaining your aunt's name for you could be put in as supporting evidence.
My name is ***** ***** I have been a solicitor for more than 30 years.
There is no requirement for an affidavit at all and the Land Registry will not hav eto be involved at all
The only person who needs evidence that you are the person in question is the Executor and his her or their lawyer.
Yes she is exceeding her authority - the house is yours and if you can pay the charge then that is your decision