What do I do if I find a passport I'd reported lost/stolen?

Never travel on your passport if it has been reported lost or stolen. You run the risk of being stopped at border crossings, as Interpol keeps a record of all reports of lost or stolen passports.

You should return the passport to the Consular Section of the Irish Embassy in Kampala:

Box 7791
Plot 25 Yusef Lule rd.
Nakasero
Kampala