Dear Concerned,
In reference to you notes above - everyone is blessed with his certain Fundamental Rights and which has right to access you own house in such a case if it taken away by some you can fight for it .
Here are options available.
1. Put a notice in front of your house for NO PARKING in front of the gate -Tyres will be deflated
2. Write an application to your nearest police station that your gate is being blocked by people coming to bank , hence bank need to put a Guard to take care of this parking.
3. Alternatively employ a guard at your gate who should stop people from parking in front of your gate. (You can try this for a month to see results)
4. As the gate opens on a public road - there is not much you would be able to do other then the above.
Best of Luck