I think that the moral of the story is, as ever, to heed the old researchers' adage of making sure that you understand why, how, and for what purpose a document was made before attempting to make use of that document.
Digitisation has given us all access to a vast range of documents, in an instant, that would previously have taken a lifetime to track down. Compared to the amateur genealogists of our parents' and grandparents' generation, we are exceedingly lucky in what we have available to us. BUT free availability of information is a double-edged sword. We can turn up a record online ever so easily. Finding out what it is, and why and how it was made, may be a little more difficult.
TUTORIAL ON WILLS, PROBATES AND GRANTS OF LETTERS OF ADMINISTRATION (Part 1)
Until 1858, the administration of wills and estates was a matter for the ecclesiastical courts, not the civil courts. The procedures which they adopted were largely adopted from 1858 onwards, so there is an essential continuity of terminology, processes and documents. All that changes it the court that administers the process, and the archive you have to consult to obtain copy documents.
A Will, or "Last Will and Testament", is a document in which a person dictates how they wish their worldly possessions to be distributed after their deaths. Traditionally it was made by a person on their death bed, but in recent years it has become much more common for people to make a will "just in case" at an early age, and to review it from time to time. In part this is because with the coming of the railways and the motor car, sudden death in catastrophic circumstances, with no time to make a will, became much more common (or, at least, people became much more apprehensive of it).
It is all very well and good MAKING a will ... but there needs to be SOMEBODY who will actually carry out your wishes and put them into effect (or "execute the will") after you have died. These people are normally named in the will and are called the "executors". You can have a single executor, or you can have more than one executors.
When you die, the executors have a right to possess your property and to deal with it, BUT ONLY FOR THE PURPOSES OF EXECUTING THE WILL. This right arises FROM THE WILL ITSELF, and in the case of a simple estate, where all of the deceased's property is in the form of chattels or cash which can simply be picked up, taken away and distributed, there is actually no need for the executors to go to Court for a Grant of Probate. They are entitled, by virtue of the Will itself, simply to take the goods and money and distribute them in accordance with the terms of the will.
In practice, however, very few estates are this simple. Most people have a bank account or other property which is held by a third party in some way or another, and where this is the case although the executors are ENTITLED to demand the property be given to them, the bank or other party will be understandably reluctant to hand it over unless the executors can prove their right to the property. The simplest way to do this is to obtain a Grant of Probate, which is a formal document sealed by the Court, notifying the world at large that (a) the deceased has died; (b) the deceased made a will; and (c) the person(s) to whom the Grant is made are entitled, under the will, to administer the deceased's estate.
In order to persuade the Court to make such a Grant, it is necessary for the executors to prove to the Court that (a) the deceased has died; (b) that the deceased made a will; and (c) that the person(s) seeking the Grant is/are the executors named in the will. This is normally done by simple administrative processes, with the executors making sworn declarations to this effect, exhibiting the death certificate and the will, and stating that so far as they are aware this is the last will that the deceased made. In cases where there is a dispute, however, then the Court can hold a full hearing, and the witnesses to the will may be called to give evidence to the Court about the manner in which the will was made and signed, whether the deceased was under any form of duress, whether he or she appeared to be of sound mind, or whatever, depending upon the circumstances of the case.
