Gratuity dues

If the establsihment works for 6days/week or less than 6days/week and if you have worked for 240/190 days in each year and for 240/190 days in last/5th year, then you should be eligible.

If the company/employer on its own does not supply 'Notice of Determination of Gratuity' and payment within 30days from LWD then you shall be eligible for interest @10%pa.

If the company has noty supplied these then you may submit FormI preferably by Redg. post, addressed to good offices of appointing authority,MD and mention that these have not been supplied to you despite representations.

If the good offices also do not provide relief then you can approach ALC/DLC and he/she may issue FormN to company. YOu can appear in person or thru authorized representative.

I presume that you are NOW in UK but worked in India. 

Since you have worked for more than 5 years (2009-2016) you are eligible for grauity. You have to claim it before the employer in FORM I and if they do not pay within a month, you are free to claim in FORM N before the controlling authority under Payment of Gratuity Act. 

As claiming through FORM N is a legal procedure, your presence will be required during your evidence and cross examnination. Other than that, your lawyer/ representative can handle the situation. 

You have posted that " I have not been issued letter of acceptance of resignation and release letter."

Why these were not issued and supplied?