Your Personal Savings Allowance (PSA) applies to all your savings interest combined, not per account.
For example, if you hold:
Your total savings income would be £1,100. If you’re a basic rate taxpayer, £100 would be taxable.
If you're close to your PSA, opening multiple fixed rate bonds could push you over the limit, so it's worth monitoring all your savings products together.
That being said, savers can open multiple fixed rate bonds where the terms end at different times. This way not all your money is tied up all at once. This can be referred to as a fixed rate bond ladder strategy.
You’re responsible for ensuring that any interest earned above your Personal Savings Allowance is reported to HMRC and the correct tax is paid.