With no spouse and only her children, under the rules of intestacy, the house and all the assets would be divided equally between the children.
You would have extra claim on house if you had contributed to the fabric of the house, not just the bills. It’s not an easy claim to bring would be difficult to prove.
The fact that you may have lived in the house for the last 40 years does not give you any more right to exclude your siblings than it does for them to exclude you.
Someone has to take control of the estate and the property and apply for probate to allow the property to be sold.
Your rights regarding the estate remain the same whether you move out of the property or remain in it. However from the date of your mother’s death you would be liable to pay an occupational rent of 1/5 of the market rent in respect of your occupation of your occupation of your 4 siblings share.
Can I clarify anything for you?
There are 5 children of which you are 1.
You own the house between you 1/5th each on your mother’s death.
Hence, if you remain in the property, you cannot only live in your 1/5 of the property, you have to occupy the whole and hence, whatever a market rent for the whole property would be you would have to pay 4/5 of that, 1/5 to each of your siblings in respect of your occupation of each of their shares of the property.