Settlement deed, sale and purchase of house

Dear Sir/Madam, My mother had made a settlement deed in favour of us and my brother mainatining a life interest for our house that was built by my late father. We have now sold the house and wish to buy a self-contained flat for my mother. As per the sale deed, a third each of the proceeds were received by the 3 of us. We have had conflicting opinions by 2 auditors on whose name the flat should be purchased ? One auditor says that the flat can not be be bought in our mothers name as my mother only had a life interest in the property and she is not entitled to any proceeds from the sale of the property. He has advised that buying the flat in her name would result in her being taxed and to account for the money and be taxed (she is a widow and has no income of her own). On the other hand, another auditor suggests that we could buy the flat in her name and she could be the owner as well, as she had received the sale proceeds and paid TDS as the per the sale agreement which means the sale agreement was executed as her being a legal heir despite the presence of the settlement deed. Which is correct and what should we do as we do wish to buy the flat in her name but do not wish to be unneccarily taxed due to ignorance. Please advice if we could add her name to the flat we buy? Should all 3 be joint owners or my brother and my mother be joint owners to reduce CGT ? We do not want to be penalised