Is there a legally mandated filing fee and/or deposit in the last instance?

Parliamentary Elections Act,No.1 of 1981

102. (4) Every appeal preferred under thissection shall, for the pU'rposes of. the application of the Stamp Ordinance, bedeemed to be an appeal in a civil action of the value of ten thousand rupees.

103.(1) At the time of thefiling of a petition of appeal or within three days afterwards, security forthe payment of all costs, charges and expenses that may become payable by theappellant shall be given on behalf of the appellant.

(2) The S;€curity shall be anamount of not less than ten thousand rupees. The security required by thissection shall be given by a deposit of money.

Source:

http://www.ifes.org/~/media/Files/Publications/Election%20Law/1981/IFES_18/EL00120.pdf