Hi urban if you asked me which notes the doorbell was playibg, I could tell you tout de suite (its usually a major third apart, and more commonly B and G!).
I believe I’ve always had the skill, but it was discovered by my piano teacher when I was nearly 7 due to a mix-up with where middle C was ‘supposed’ to be.
I used to work for a record company, but I now teach music in a secondary school.