Thanks for the advice Chris - i think i've cracked it now.
I've uploaded the TomTom One POI file here - http://homepage.ntlworld.com/kevin.dunnill/TMA_TomTom_One_UK_POI.zip with a brief instruction file of how to install it. Hope someone apart from myself finds this useful!
Fitz - if you see a tall bespectacled gangly fellow on your travels on your next venture on the moors, chances are it could be me!
Kev.