There is no certain way to be absolutely sure there is no later will, and the way the law deals with this is that if a person applies for probate presenting a will, part of the process is that they first advertise that they are applying for a grant of probate on that will in order to alert anyone holding a later will that they should come forward. Once probate is granted on a will, if later on a more recent will is found, the executor of the earlier will will be protected from liability for any incorrect distribution.
As regards ***** ***** lawyer being coy about whether they hold a will, you should refer them to section 50 of the Wills Act:
as any person listed as a beneficiary under an earlier will is entitled to inspect and copy any subequent will if held by a party. If you write to them referring to this section and they fail to acknowledge they have a will, then almost certaily they won't have a copy and could be in trouble if it later turns out they do.
Just because you were removed as a PoA does not mean you were removed as a beneficiary or that the deceased changed their will. The PoA may have been removed for a variety of reasons, including that the deceased had thought it unfair to burden you with being their PoA, so unless someone comes forward with a new will shortly, you should proceed on the basis the will you have is the last will, and if you are listed as the executor, then that means applying for a grant of probate.
i trust the above assists.
Good luck and PLEASE RATE MY ANSWER.