Dave Again

My Mum is 92 and her husband (my Dad) died recently. She now has 4 pensions and no other income: 1. State Pension (enhanced due to Dad dying) 2. Teachers Pension 3. British Gas Widow's Pension 4. British Army Widow's Pension Combined income will be about £30,000 a year Should she complete a Self Assessment tax return or will all income tax due be deducted automatically ? Thank you