Try the Vanguard questionnaire to help clear the fog
https://investor.vanguar...nnaire#modal-start-quiz
For any fixed interest allocation (bonds and cash), I'd recommend buying individual Gilts and Corporate Bonds with a duration to match each year or two of your 15 year horizon plus some cash or money-market funds.
Whatever assets you choose, you MUST KNOW ITS PURPOSE & ROLE within your portfolio.
Know WHAT you hold and WHY you hold it.
Start with existing holdings.
Out of interest, if the market crashed 30-50% on Monday and stayed down, where would that leave your thought process?
Would give strong consideration to annuity.