Sorry my uncle was not married and had no kids. He lived alone and farmed the land by himself with the only one getting an income from the land.
From Citizens advice - I have underlined the relevant parts. As far as I know the land cannot simply be sold because your uncle is not the legal owner or the officially appointed administrator.
I would also question the Auctioneer's role in this and wonder why he has not requested proof of ownership or some form of official permission.
I will have another look for you tommorow to see what I can dig out - but I don't think that you can "self appoint" yourself as an executor.
What happens if you die without a will or your will is invalid
A person who dies without a will is said to have died 'intestate'. If you die intestate, this means your estate, or everything that you own, is distributed in accordance with the law by an administrator.
To do this, the administrator needs permission in the form of a Grant of Representation. When a person dies without a will or when their will is invalid, this Grant is issued as Letters of Administration by the Probate Office or the District Probate Registry for the area in which the person lived at the time of death.
Rules
Distribution of your estate when you die intestate or have not made a valid will
The legal rules governing the distribution of your property apply:
When you have not made a will
When the will has been denied probate because it has not been made properly or a challenge to it has been successful
When the will does not completely deal with all your possessions.
In these cases, after debts and expenses have been deducted, the estate is distributed in the following way.
If you are survived by:
A spouse/civil partner but no children (or grandchildren): your spouse/civil partner gets the entire estate.
A spouse/civil partner and children: your spouse/civil partner gets two-thirds of your estate and the remaining one-third is divided equally among your children. If one of your children has died, that share goes to his/her children.
Children, but no spouse/civil partner: your estate is divided equally among your children (or their children).
Parents, but no spouse/civil partner or children: your estate is divided equally between your parents or given entirely to one parent if only one survives.
Brothers and sisters only: your estate is shared equally among them, with the children of a deceased brother or sister taking his/her share.
Nieces and nephews only: your estate is divided equally among those surviving.
Other relatives only: your estate is divided equally between the nearest equal relationship.
No relatives: your estate goes to the state.
Edit - the assets should go into probate first, the executor/administrator appointed, a sale organised and then equally divided as set out above.
You should contact the probate office in your area for further details.