WMG / Peek-a-Boo Poo

Heidi was born a year after the events of the first book.

In the second book, Heidi seems to be two years old, since she's starting to be potty trained, and two is the age that Alfie was potty trained. Alfie is said to go to school, so he must be older than four (since anything before that is preschool age), yet he can't be that old, since he enjoys flushing the toilet. Perhaps, in the second book, Alfie is five, which is three years older than Heidi, putting her birth at a year after the first book.