Ask an Property Solicitor. Get an Answer ASAP.
Thank you for your question
My name is Clare and I shall do my best to help you
You are indeed entitled to give her two months Notice (ending on the rental payment date)
Please ask if you need further details
The form you need to use is here
on the basis that you wish to return to the property
You wish to return to the property to deal with the sale.
Alternatively place a sum equivalent to the deposit in a scheme and the use a s21 Notice