AS3 or TR1 and probate

Good afternoon.

In a situation where a couple live as "tenants in common" with the property shared 50% / 50% and one of them passes away, which form is used to transfer the deceased 50% share to the beneficiaries (2 sons and 1 daughter - all executors of the will and trustees of the 50%), would a TR1 or an AS3 be used?

There is no Inheritance Tax due and no other need for probate except (possibly) to assent the 50% of the property to the beneficiaries.

Is probate required for the executors to remove the deceased from the will and add the 3 names of the beneficiaries?

Thank you.

Good Afternoon Andrew - the 'simple' answer is neither as you can't transfer a share. The legal ownership, which we register, can only be transferred as a whole.
The 'better' answer is that if the legal ownership is to be transferred to new legal owners, for example the surviving joint owner plus the three beneficiaries, then form TR1 would be used. The surviving joint owner would transfer (transferor) to themselves plus the beneficiaries (transferees)
There are a number of similar threads on the forum that explain this in more detail and reference tenants in common, beneficial shares and more 
Such as Death of a tenant in common · HM Land Registry 
 

Good evening Adam,

Thank you. I`m afraid I`ve confused the situation; I`ve spent so long reading articles and appear to have gone down a rabbit hole after reading an article on assent. 

Thank you for the link; I`ve copied a section of your reply in the link (pasted below) to ensure that I fully understand it. 

Because the deceased 50% is now in a trust (as per his "mirror property protection trust last will and testament"), then no changes need to be made to the deeds.  If I`ve understood correctly, that saves a lot of paperwork.  Please correct me if I am still wrong.

Thank you,

Andy

"sometimes only an update re the death as it all depends on what the interested parties expect/want to happen next. But even updating the register re the death is not required until such time as the property is updated for some other reason for example sold

 Why is that? Well, we register the legal ownership and the tenants in common/trust/wills all relate on the beneficial ownership. And in many cases when joint owners make such arrangements the register is only part of the consideration following the death as that's already been planned for"

Good Morning Andrew - it's a virtual warren of such holes re legal and beneficial ownerships but you have come out of one of the 'right' holes re your conclusion. You are not wrong
Many joint owners, when setting up their wills/such trusts, do so expecting nothing to ned to change until both have passed away. As such when one dies there is sometimes nothing to do re the legal ownership (which we register) 
The death is a fact that can be proven as and when; each of the beneficiaries is aware of what has happened to their share (still exists as part of the property value); the surviving owner remains in situ; and everyone knows what's what so to speak.
It's always best to discuss such things following a death just to ensure every interested party is on the same page especially re wills, trusts, IHT and other things that we don't register.
The option to transfer the legal ownership exists but should be considered carefully as owners/beneficiaries don't always consider the impact of being a property owner or say an owner of more than one property

Good morning Adam,

Thank you very much.

Andy