I remember getting it as a freebie with a magazine, probably in the early noughties.
Main characters are a woman who is a single mum to a little boy, and a man who was her teenage boyfriend. Man has a fiancée with rich parents who lives in Maida Vale. When they were teens he went to boarding school and he had a dad described as a spiv. They meet by chance as adults in a toy shop when she’s looking at expensive games consoles but is actually planning to buy a kite for her son. Illicit romance ensues.
Any ideas?