Death of joint owner 4 years ago

My uncle died 4 year ago at the start of the pandemic, leaving behind my aunt, his widow. They were joint owners of their property.
My aunt is now going into care so we will have to start selling her assets. They had no children and my sister and I have joint Power of Attorney over her affairs and are both named on her Will.
In the confusion of the pandemic and the fact that we dont live near my aunt, we never informed Land Registry of his death. Can we do this now? Which forms and evidence do we need? If not,  will it cause extra work when we sell her house to pay for her care?

Stephen - To start with please refer to our Practice Guide 6 and the guidance about dealing with land and property when someone has died. 

They will help explain our procedures and requirements based on what you wish to do.  Apart from that, you need to seek legal advice on how to proceed as that is not something we can tell you.