I never mentioned Liverpool or Norwich, Nottingham to Leeds was what was bring discussed and the original plan was to MML to run London to Leeds via Nottingham with 9 car 222s. Those plans were shelved and the 222s didn't enter traffic, sitting around for a while with various options including export to Ireland being considered before they finally did enter traffic with MML.
The route was still considered to be worthwhile however so Northern were contracted to run the route as a semi fast service with 158s with Sheffield and Leeds crews learning to Nottingham (they already had work to Chesterfield and always had done).