Help understanding my parents wills

[Viavito]

My mum died in December of 2022 and left a will containing the following
"I give to my grandson X, my granddaughter Y each free of all taxes and death duties the sums of One thousand pounds subject to such gift taking effect after the death of my spouse."
My father died in July of 2023 and left an identical will ( I think the term is that they are mirror wills) containing the same bequests as above.
My question is how much should X and Y inherit?

[atticus]

What you say suggest that there are 2 sets of legacies to be paid.

[Viavito]

Thankyou for your reply.
So in the example above each grandchild would receive £2000, a gift of £1000 from my Mum and a gift of £1000 from my Dad but only payable on the death of my Dad?
According to the final estate accounts the solicitor who is administrator has only paid one gift of £1000 to each of the grandchildren.
I have questioned this and the solicitor is saying the wills are badly drafted and open to interpretation and now need to be examined as contentious.
I just want to make sure that my parents wishes are correctly carried out.