Property Transference with a Family Trust

My father has died. My parents, years ago, redid their wills so that when they die, their home would pass into a family trust. (They live in an average-priced 3-bed house in Surrey) 

When they had their wills redone and set up the Family Trust, they became Tennant in Common. My mother has received a letter from the company they used stating that conveyancing needed to be completed to transfer the house into the Family Trust.

My question is does there need to be conveyancing or can I complete the relevant forms for the land registry to notify of my father's death and transfer his share into a family trust. There is no mortgage on the house.  My mother is the primary beneficiary of the trust and will continue to live in the house.

Many Thanks

Clare - I am sorry to read of your loss
Whilst there is no need to use a conveyancer when updating a registered title I would always recommend seeking legal advice/assistance as appropriate, especially when dealing with a family trust
We register the legal ownership and if that was in your parents joint names then it currently lies with your Mother following your Father's death. 
The tenants in common/Family trust/wills relates to their beneficial ownerships and it is that specific aspect you should seek legal advice/assistance on. There will be options to consider as to whether the legal ownership does need to be transferred and the register updated
Once you have decided what's to happen then our online assisted guidance walks you through the registration requirements - HMLR Guide: Start - External  · HM Land Registry
Land registration is complex, designed to protect legal and financial interests in property. There can be significant consequences for any error. Please consider seeking legal representation. Before making an application without legal representation, it is important to consider the benefits of using a conveyancer.