Really sorry to hear about your mum, hope you and your family are okay.
We’ve been through this recently although much simpler than your case – one house, some cash and split between two.
We did probate ourselves which was quite daunting but once you start it’s okay.
One thing to remember is that is that if your mums partner has also passed away and didn’t use any of the inheritance tax allowance you can use ‘doubling up’, where you can double the allowance when clearing up this estate.
Simple put assuming its just nine of you involved then everyone gets a ninth and if the wanted to stay where they are they would need to pay the value of the property back into the pot – so they buy the property but still get a ninth of the estate.