Hello, I am Keith, one of the experts on Just Answer, and pleased to be able to help you with your question.
When you receive a legacy it is outside the scope of UK taxation and there is no tax to pay. However, under Irish Tax Law Capital Acquisitions Tax may apply depending upon the size of the deceased's estate.
Here is an extract from Wikipedia:
'Capital acquisitions tax is charged to the recipient of gifts or inheritances, at the rate of 33% above a tax-free threshold. Gifts and inheritances are gratuitous benefits; the difference is that an inheritance is taken on death and a gift is taken other than on death.'
That is your only problem here. I do hope that you have found my reply of some assistance.