Removal of a form A restriction

I am one of 3 names on our property title. The other 2 names (family members) have sadly passed away, thus I am the sole beneficiary. I wish to sell the property, but there is also a Form A restriction (tenants in common), which I think was added to vest 50% beneficial interest to my father and 25% each to myself and my brother. Is probate required for my brother's estate  in order to apply for restriction removal (probate has his original will), or is an uncertified copy of his will (can't certify without original), death certificates and probate for the other family members sufficient? Thank you.
 

Steve - when joint owners die the legal ownership passes to the surviving owner to deal with. The legal ownership is always dealt with as a whole and as a result where there are joint owners, and their number is reduced to one, probate is not required.
The 5 shares, trust, wills etc you refer to relate to the beneficial ownerships and a form A restriction is often applied for to protect such beneficial interests as it restricts a sole surviving owner as per the restriction wording.
As you wish to sell there are two options to consider
The first is to apply to cancel the form A restriction using forms RX3 and ST5 - you would need to be the sole legal and beneficial owner. See PG 6 section 8 for guidance Devolution on the death of a registered proprietor (PG6) - GOV.UK
Option 2 is to appoint someone to act with you and together you then sell (transfer) the property - see PG 21 section 6 for guidance Using our forms for complex and more unusual transactions (PG21) - GOV.UK 
We are not concerned with the wills or beneficial shares but you should be as if others have a beneficial interest then that can be realised with regards the sale/purchase monies but as posted not a matter for us to deal with or be concerned by

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.