Tax on interest for deceased person's estate

My mother died last year and I am the executor of her estate. She had around £4,300 in interest from savings accounts and a further £1,300 was accrued by the estate before it was paid out. I've been expecting something from HMRC since April as I thought they got automatic notification of interest amounts, but it seems I have to write in with details of the interest. Her total income was just over £13,000, so she would have nearly the full £5,000 interest allowance remaining. Is the normal £1,000 interest allowance included in this or is it extra? Will I have to pay tax on the post-death £1,300? Can the beneficiaries reclaim this tax? If so how?

Hi,
Please contact the Inheritance Tax team for advice:
Inheritance Tax: general enquiries
Thank you.