No not his diary, and it would have helped if I'd spelled it correctly, as "Santa Claus in Summer". It's a children's novel. McKenzie took all the traditional nursery rhymes, one or two folk tales, put them in a jar, shook them up and the book is the result.

It centres on the village of Banbury Cross (where all nursery rhymes seem to exist) and where the children have become excessively well behaved. The story is a plot by Puck and Santa Claus to restore the status quo of mischievous children. There's a lot more plot to it, than that - Midsummer Night's Dream is in there, too. Sadly I do not have it, and it's out of print, too.

Hands down my all-time favourite children's book.