Yes i know about trusts.
You don't want an income generating asset in a trust (like a bank account) because of trust tax: annual & periodic reporting.
Uk IHT trust solutions that "will pay you a fixed monthly income" (i'm contradicting myself for your simplicity) are called discounted gift plans. There a very few solutions whereby you, as the settlor, can benefit, as that becomes a gift with reservation, but this is one.