In a situation like yours the developer is not the transferee or buyer of the flats as per the Transfer of Property Act, 1882 under the Joint Development Agreement. The sole ownership lies with the owner of the land,
Once the plan is approved, the owner should get an allocation agreement done recording the constructed area which comprises his share and the area going to the developer. Once the building is ready and the allocation agreement is done, it is better that a deed of declaration is executed recording the constructed area, which would reflect the area constructed for the site owner under the joint development agreement
The license/authority to enter the land is typically given by way of a power of attorney issued in favor of the developer.The general power of attorney should be registered on appropriate value stamp paper with the concerned authorities (registrar) in order to be legally binding on both parties.
For the purposes of transfer of the constructed space by the builder, the co-operation of the owner is highly essential. Once the construction of the flat is constructed and occupancy right is granted by the competent authority to the owner, the owner will himself execute the sale deed in favour of the flat buyers. The developer will have the right for specific performance which shall be specifically enforceable in a court of law if the land owner fails to cooperate with the developer in selling/leasing the built-up space on the land.However, in case of breach of the terms of the development agreement, the land owner would have the right to revoke the power of attorney.
Further after construction of flats is completed and handed over to the purchasers, the flat owners or the builder will form a flat owners association after which the conveyance of land shall be executed in favor of the association/society by the landowner has to be executed, till then the land owner shall be the owner of the entire area excluding the constructed flats, thus there is no reason for the promoter to retain the original land title.
You may ask him to hand it over.