Commercial property advice



New Member
My sister and I were left a 38% share in the freehold of a retail property on the death of our mother, the remainder is held by various family members.
The property was leased in 1946 for 99 years and has subsequently been subleased.
Does anyone know if:
1) we should inform the Land Registry?
2) do we, as executors, need to draw up an Assent document?
3) Do we have to have a Deed of Appointment to replace mums name on the schedule?
4) do we have to wait until the term is complete to sell the property/freehold?

sorry for asking a lot of questions but I'm trying to fathom this out.
Thank you for reading and I hope someone can give some guidance.