Could not find Irnham in either an atlas nor Getty's Thesaurus of Geographic Place Names. Was contacted June 1st 2005 by Alan Stennett who contributed "Irnham is a very small village north-east of Corby Glen, which is north-west of Bourne. It is the village featured in the medieval illustrated document, the Luttrel Psalter." Found it with Multimap as about 7 miles NNW of Bourne.