Hello wozzle
Your guess is correct, what was Great Street is now Manor Road but I don't know when it changed - I'll ask around, someone in the village will know.
Re the old map, look at old-maps.co.uk they have one for Sulgrave 1887. The vast majority of houses in the village still don't have numbers, only names - is there a house in particular you're looking for?
Regards
Jamys