Changing from partnership to sole trader

My wife and I have operated as a general partnership for several years. I have now retired and we have closed the partnership. My wife will continue to work as a sole trader. My question is does she need to register as a sole trader? She is already registered for self assessment. The partnership was not VAT registered and we do not pay NIC as we are receiving our pensions. The information I have found online is contradictory.

Hi.
Please contact our Self Assesment team so we can check your account:
Self Assessment: general enquiries  
Thank you.