You can file an application in the said sub registrar office along with an affidavit with the documents of correct name . If the same is not done from there you need to approach court. 

1)deed of rectification has to be executed by seller or his legal heirs  to rectify the spelling mistake in name 

An affidavit for same can be made by children of grand father before notary.

Partition deed will execute, what difficulty you are facing. Spelling mistake can be justify by affidavit.

These mistakes can be corrected through a deed of confirmation.

In this case your father and his siblings have submit affidavit regarding spelling mistake in name of their father to sub registrar.

Or they can execute a rectification deed with seller of that property.

1. Execute an affidavit before the local 1st class judicial magistrate affirming that inadvertently the name of your grandfather was wrongly typed in the property papers/deed which is required to be correc ted.

2. After the said affidavit, the name of your grandfather wronglyt mentionjed in the property papers can be corrected.

The name of the grandfather if given properly and the department made a mistake then you may apply for correction, but if that the given name is not proper then yo may issue a notice to the seller demanding him to execute a rectification deed to rectify his name.

1. As per the information mentioned in the present query, makes it clear that there has been mistake in grandfather name in the property paper and now he is no more.
2. In this situation, I would advice you to not to go for the name correction as this would not server the purpose.
3. In fact, all the legal heirs give an affidavit along with the succession certificate in he civil court of law that he was their father.
4. Only then there can be something done for you.
5. As once you have the succession certificate then there would be no problem in distributing the property amongst all.