No suit shall be instituted against the Government and no suit, prosecutions or other proceeding shall be instituted against any officer or servant of the Government in respect of any act done or purporting to be done under this Act, unless the suit, prosecution or other proceeding is instituted within six months from the date of the act complained of:

Provided that, in computing the period of limitation under this section, the time taken for obtaining sanction under the sub-section (1) of section 51 shall be excluded.