Can child on UK general visit visa travel other adult (not parents)?

[guruketepalli]

I am an ILR visa holder. I helped my relative family to process UK general visitor visa(Father, Mother, and 6 years child boy). They all got the UK visit visa. In the child boy visa, it is mentioned that the visa is valid if accompanied by passport numbers (Father and mother passport numbers mentioned). Due to some personal reasons, both parents are not traveling. Now, my question is that this 6 years child boy can be accompanied by some other adult (Grand Mother or Father having UK general visit visa) by taking a consent letter from his parents?

I checked the UK gov website (https://www.gov.uk/standard-visitor-vis ... e-under-18), it is given that child can travel with parents consent. I wanted to validate my understanding is correct.

Could you please advise on this?

[guruketepalli]

Could you please answer my query?