New asset found after grant of probate

I have a relative who died more than 25 years ago, when probate was granted. I was the executor. I have received correspondence from an investment bank advising me of a dormant investment account belonging to that relative. I do not have any paperwork relating to the executorship and probate. I remember who were the beneficiaries of the estate to whom the proceeds of the dormant account need to be paid. But do I need to report anything to HMRC? How can I find out if any tax is due?

Hi ,
 

You will need to check with the Inheritance Tax Office for  probate value to be changed. For funds in the bank, any interest generated will be liable to income tax . Thank you .

Thank you, HMRC Admin 17. This wasn't a bank account but an accumulating investment fund, which grew in value, not paying out dividends or interest. So should the growth in the invested fund value from the date of my relative's death to the date when the proceeds are received be subject to capital gains tax and not income tax? And if one of the beneficiaries is Irish (Eire), what tax is payable on his sum due?

Hi PAKenT*1 PAKenT*2,
New asset found after grant of probate would be an Inheritance Tax matter. please refer to previous reply for link to guidance. 
Thank you