If I sign something today and write signed 1 Jan 2017 that breaches the statute of frauds but might have no consequences and not be a problem. Better to sign today either not say when signed or say signed 3 Feb and then separately have a clause saying effective date 1 jan 2017 - the latter is done every day perfectly lawfully for loads of agreements and breaches nothing.
On the other hand you cannot make information secret after it is disclosed so back dating a secrecy agreement eg woudl not work.
If say parents made a gift of money to an adult child. Then child marries, marriage in trouble, suddenly the parents pretend it was always a loan and back date a loan agreement the divorcing spouse could bring evidence to show the document was not true - it was a gift always not a loan but that is not so much about dating of it but because it was a lie and tried to change things after the fact.
Most legal documents are not required by law to have a date on so dating is not a huge issue for them.
What does it say in regards to the date. Eg does it say This trust is dated 1 January 2013?
Dates can be important. In the Abramovich case about when a verbal contract (yes they are often valid by the way in some areas of law) was made the other party produced 2 or 3 different dates throughout the case and in each case A could prove he was out of the country on that day so could not have reached agreement in person with the person on that day as alleged. So that went to help prove which side was the liar.
So in your case if it says 2 March but you were all at a family wedding on video no that day and the father could not have signed but he could easily have signed no 3 March and just muddled up the date then the wrong date may not matter. Eg if this document was sent by email at the relevant time even if the date is not quite right they may be able to show it was sent through looking at old emails or they may be able to prove nothing of the kind and the ink or paper might show it was made last week not 10 days ago, just to get round paying you anything.
Are you due to file any evidence? Just say factually in a statement why it couldn't have been the date, why in fact it couldn't have even created anywhere near that date (as you said months in your OP) and without labelling it say why you think this is Eg I believe my ex and his father have drawn this document up and back dated it to try to reduce my claims against the property and that ex's father does not have any true beneficial interest.
Hi there, I've read your chain with huge interest as I am in a very similar position.
We are getting divorced and my father in law is laying claim to over 50% of our matrimonial home and our buy to let. He wants to sell both and this does not give me enough money to adequately rehouse myself and our daughter (who lives with me).
Do you have any update on how your case panned out?