"I found a Will from my grandad (his father) in his home."
Is that a signed original will or a copy of the will? Is it the latest will?
Once an estate has gone through probate then the will becomes a public document and anybody can see it. It's simple to do and costs £1.50
https://www.gov.uk/search-will-probate
You can then check the date on the will used for probate just to check which is the latest will.
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Assuming this is the latest will and a certain amount of money was left to your father then this now becomes part of his estate and his executor (yourself I assume?) becomes responsible for recovering that money.
Even though your father has now passed away, that money is still his.
Also, an executor is required to keep account of the assets and how and when they have been distributed.
As a beneficiary, you (as executor of your father's estate) are entitled to a copy of the estate accounts to see exactly how much the assets were and exactly who got what.
You need to send a letter to your uncle saying that you want to see an Inventory and Account of your grandfather's estate and warn him that he may be held personally responsible for any legal costs if he doesn't. If he does not provide this within 14 days then you request a Summons form from the probate registry where probate was done.
He will then be sent a court summons to provide those things.
This will show you what assets your grandfather left and what has been done with them.
"...as I don’t want to rank up high legal fees."
You can do the above yourself.
Your next steps after that though, depends on what you find. If your uncle has taken the money then you're likely going to need a solicitor to recover it.