A.J.
I am not familiar with Manuka honey, but I do think honey is a great alternative to some medicines since your child is over the age of 1. To clarify the previous poster, honey does not carry listeria (this causes illness in all age groups), it is the botulism spores (adults almost never affected) that are life threatening to infants.
I use a combination of the following; benadryl, saline, vicks, nasal spray (little noses brand-not saline), a cool-mist humidifier, echinacea, and extra vitamin C.
A.