Barry and thanks Just Answer.
My name is ***** ***** am happy to assist you with your enquiry.
As regards ***** ***** Will, a party can only place a Caveat if they believe the Will is invalid.
If a party wishes to make a claim against the Estate, on the grounds that they have not been left reasonable financial provision, this needs to be done within 6 months from the date Probate is granted.
However, on the basis that you were not financially dependent on your father, you have a pretty much zero chance of making such a claim, unless you had done something detrimental to your well being, benefit of your father, on the understanding that you were to inherit more from your father than he left you. (The classic example is where , a child gives up work to nurse a parent, on the understanding that they would be financially rewarded in the Will). I'm afraid if it is just a case that you feel you hav been treated unfairly, this on its own, does not give you the right to contest the Will.
As regards ***** ***** if your sister is in agreement, there is nothing stopping her from changing how the Estate is distributed. A simple Deed of Variation can be drawn up at any time within 2 years from the date of death, setting out the "new distribution percentages" and which acts in legally changing the terms of the Will.
I hope this helps you and sets out the legal position.