Hi. My name is*****'m looking at your question now and will post my answer or ask for more information here in a short while.
Interest is taxable when it is paid so if it is paid in each tax year, then the allowance will be applied to it accordingly. If you get all the interest at the end which the word "deferred" implies then it will be taxed in the tax year when the bond matures. Your annual allowance will then be applied to that. You cannot carry forward an unused annual allowance.
I hope this clarifies things for you but let me know if you have any further questions.