The student room has a bank of (risible) personal statements.
I expect admissions tutors are very weary of students wasting valuable words on stupid anecdotes about how they became interested in the subject.
I have also noticed that a lot these anecdotes don't actually relate to anything relevant subject-wise.
Surely you'd be better off talking about how your intellectual curiosity led you there. Like doing punnett squares didn't explain bees and ants so you watched a video, read a paper, read a book and found out more and then...realised there was more to find out and even better, more stuff we don;t know and you want to be that person to research.
Or wandering why SE Asians are more vulnerable to coronavirus > socioeconomic and cultural factors that lead to overcrowding, customer facing occupations, family structure. Or the neolithic farming transformation > rice subsistence --> epigenetics of type 2 diabetes, and then off on a tangent possibly golden rice and GM crops.
If you're a "pyjamas on fire" student then you're seriously underestimating the competition if its a Russell group you're after.
I'm going to remember "pyjamas on fire" as an example of what not to do.