As already explained in this thread teachers of private schools are eligible with retrospective effect from 1997.
The employer has to ........................on its own supply the notice of determination of Gratuity, and Payment of Gratuity even if employee has not submitted any application........................And if the employer has not tendered the payment within 30 days of separation of employee it has to tnder interest @..................(last it was 10%pa).
There is no limitation.
You might have sent FormI by ordinary post and may show it as and when required.
The employer is likely to agitate on delay in application by employee however the employee may persist that the employer has neither supplied notice of determination of Gratuity, and Payment of Gratuity (and has not produced the proof of letters/redg. post sent by employer being returned from address of employee).
If need be delay can be condoned.................................and you may go thru:
"landmark judgment of Punab high court for condonation of delay in payment of gratuity"
and download if from following threads:
https://www.lawyersclubindia.com/forum/Clarity-between-gratuity-eligibility-service-5-or-4-8-yrs--28768.asp
https://www.lawyersclubindia.com/experts/gratuity-490411.asp#.Vg0vV31-jMo