Legal owner - Tenants in common

My Father and his sister owned a property as tenants in common. He has sadly passed away recently, him and sister had a big fall out a few years ago, i have inherited his share, is there a way to add myself on the title deeds? I don't think the sister will sign any paperwork.

Jaitesh - to 'add yourself' you would need the surviving joint owner to transfer the whole legal title/ownership to herself plus you. So you would need 'signed paperwork' I'm afraid.
You refer to TIC and I assume that the trust arrangement has been protected on the register by way of a form A restriction
See Joint property ownership: Overview - GOV.UK
If so then the trust and your beneficial share/interest is protected albeit you are not named on the register. If you are concerned with regards what your legal rights are and indeed how the surviving owner is 'restricted' then please do seek legal advice  
 

Our solicitor has a TP1 Form which was filled out in Jan this year, all signed and was have meant to be sent to land registry. My father has correspondence with land registry as they said they never received the paperwork. Can this paperwork be used by any chance?

Jaitesh - if the paperwork is complete and legally valid then it can be used to submit an application as appropriate - Registering land or property with HM Land Registry: Change the registered owner name - GOV.UK
Form TP1 is used to transfer a physical part of a title such as the garden ground. 

Did both named legal owners need to be on the AP1 Form or was it only the party transferring legal title?

Jaitesh - form AP1 is an application form. Form TP1 is a transfer deed so the legal deed used t transfer part of a registered title. If they were joint owners in January then they would both have had to executed the TP1.
However, reading between the lines of what you are sharing and also basing it on experience re similar enquiries submitted over the years, I have a feeling the TP1 form may have been drawn up in an effort to try and transfer a half share of the legal ownership. If so then you can't do that as the legal ownership can only be transferred as a whole by both joint owners. 
I would strongly advice you to seek legal advice to understand not only their legal and beneficial ownerships but also what impact and legal standing, if any, the form TP1 might have