Its a long shot but Im desperate to find it as I loved it.
Novel by a male author who was very young when he wrote it. It was his debut novel.
Had a hot air balloon on the front cover
Story was a girl meets a boy in park and they fall in love.
However she gets arrested for killing her father and goes to prison and he marries her cousin.
It is set in present day and the scenes where he is an old man are in the future.
Im hoping the power of mumsnet solves this for me 