Assent with tenants in common

Freehold property is registered with HMLR with no mortgage and owned by parents as tenants in common.

Mother passed away 2 years ago and left her 50% share to the 2 children, probate obtained but no changes were made with HMLR.

Father has now passed away and left his share to the 2 children as well, probate obtained.

To change registered title to the beneficiaries do we need to complete:

One assent(AS1) form and include both father & mother on this (plus AP1/ID1 forms).
or
One deceased joint proprietor(DJP) form for mother to be removed from the register and
One assent(AS1) form and include father only in this (plus AP1/ID1 forms).

Chris - One AS1 by Father's executors plus forms AP1/ID1 (for all parties).
Include a certified copy of Mothers' probate or death certificate 
HMLR Guide Page  · HM Land Registry