Jon - see
our PG 1 for guidance on how to make an application for first registration. This explains what forms and documents we will require including which deeds/documents you will need to provide to confirm your late parents' ownership
Our
online guidance also explains how to complete the form TR1 (Transfer) from the executor(s) to the four of you
We do not see the will as any transfer will rely upon the Probate to provide the confirmation of the legal authority of the named executor(s) to then deal with the estate. If your name has changed since probate was granted you will need to provide evidence to confirm that change as appropriate, for example a copy of the marriage certificate you refer to and written confirmation re the choice of new name.
I would recommend seeking legal advice/assistance as well as a conveyancer is familiar with the legal and registration requirements, can help identify the deeds/documents required, verify all your identities and also advise on wider matters such as the impact of owning the title in four joint names and what impact that may have re other property ownership, wills and more