Constructing house while the matter is in the court.

Illegal revocation of gift deed. All my queries are replied on this subject and all are anonymous in their crisp reply that "revocation" is illegal. I thank you all the experts on this forum. The matter is still in progress in the court. We have filed suit and IA praying for null and void of revocation. Meanwhile, I would like to construct a house in this piece of land irrespective of outcome of the result as I feel the case will be decided on merits. Brief facts: In 2003 father makes gift deed (unconditional) to his daughter. In the deed recital it is clearly mentioned, the intention of donor (out of love & affections), declaration and the possession i.e. "on this day, I have given all the parental and other documents with regard to this property". Since this is immovable property we have constructive possession. Within two days of registration, daughter goes abroad with her husband instructing her father to collect all the registered documents and to take custody of parental documents and for mutation of names in the revenue records. But after registration he never returns the documents to his daughter and keeps paying taxes on his name without informing his daughter. Daughter visits India 2005 and 2007. Requests the documents back from her father but father still refuses. In 2007, daughter makes one more gift deed (settlement) to her own 4 minor children and her husband as guardian. In 2008, her father along with other family members steals all the property documents, goes to SRO, makes unilateral cancellation of the gift deed made in 2003 (bypassing the gift deed made in 2007) and subsequently makes one more settlement in favour of his 2nd son in the year 2013 (after 10 years). In the cancellation he says that he still paying taxes on his name and keeps all the documents with him and therefore the cancellation. We have filed OS and IA for null and void/ After 3 hearing father dies. After one-and-half-years, the Opp. parties filed written reply admitting that the gift deed (made in 2003) was executed out of love and affection. However, they say since his father has made gift deed on his name in the year 2013 and all the records are with him he is owner of the property. SRO is neither filed vakalat nor made any written reply so far. The present stage is that we have moved LR petition (due to father's death). I have not given Interim relief so far. My question is as follows: 1) Can the reply in written statement filed by Opp. Parties is valid? I am of the opinion, that cancellation of gift deed made in 2008 itself is invalid then the rest of the registration of gift deed is also invalid. 2) Since they are making delaying tactics to prolong the case, I would like to go ahead with construction. If I start a construction do I have to take court's permission? (Currently, I am in possession of immovable land. The Revenue docts. are with Opp. parties). I don't bother about plan's approval, etc. In case If I go ahead with my construction whether the Opp. parties can manage to take stay (though their settlement deed is illegal)