Hi kec
As you are not resident in the UK, savings interest is taxable as disregarded income.
You can see guidance here:
SAIM1170 - Savings and investment income: non-residents
The effect is that the liability of a non-UK resident in respect of savings and investment income is limited to the Income Tax deducted from it or treated as deducted or paid in respect of it. No tax return is required and there is no need to register for a tax return.
Thank you.