• Whether to vacate or rent the bank

We have a (approx 4000 sq ft) land i.e. occupied by a Govt bank for decades (since my grandfather's time). Rent agreement has been lapsed and the bank has been paying the same amount since 1995. They convinced my father to pay ?10.50/sq ft (as govt bank vis-a-vis private bank can't pay more) and not willing to vacate(coz they are using the land for a long time) 
# (it was ? 3.30/sq ft earlier) 

whereas another (private) bank adjacent to our land is paying ? 35/ sq ft. 
Though new rent agreement has to be prepared.. I have some queries

1. Can we file plea to vacate the land?
2. If not.. can we negotiate on the term of other bank rent agreement, even if they are private bank and newly occupant of the land?
3. if any danger associated to lose the land if case is to be registered by both parties?