Benificiaries have never been informed and not received money from estate

xylophone

Also, the OP said there are four beneficiaries of this 20% share, but then only listed three ages.

The other beneficiary was said to be another grandchild - one assumes that the OP hasn't asked his parents (or the grandchild) about the matter.

sheramber

Two could be the same age.

Marcon

What a load of pointless sidetracking about the ages of 2 older 'children'.

OP, if you are in regular communication with one of the executors, why not try a straightforward enquiry? You refer to 'rectifying' the situation, but if this is a trust (does the will mention anything about that?), there may be nothing to rectify. Depending on the nature of the trust, the (potential) beneficiaries would not necessarily need to be informed, especially if there is a clause preventing any of them receiving a payment until the youngest has reached a particular age, which may be 18, or older if it is a 'discretionary' trust. 

rcjcch

Thank you for your helpful suggestions.  Yes there is a big age difference, as they are half siblings, but that has no relevance on the case. 
The grandchildren are named personally in the will and there is no mention of any trust fund or money being held in trust.  The fourth grandchild, and I don't know if she has received any money, is the daughter of one of the executors.

I understand that a trust fund may have been used for the youngest two children, but it doesn't make sense for the oldest grandchildren who were already their 30's when he died.  They should have been informed and kept up to date properly.

I have written a registered mail enquiry letter to both of the named executors; asking for a full copy of the estate accounts to be made available to us and a general update as to when the bequests may be completed.  We shall see what information this brings.