We'd try to get the best scans we could. But I suspect that if you put up the raw scans and any of it could be turned to an actual use, volunteers to do the tedious labour would turn up. I'm amazed at the tedious jobs people do for Wikimedia projects in the cause of getting information into the public domain.
See also discussion on wikimediauk-l (to which this is cc'd).
Currently all the maps used on en are croped to centers of population, geographical features and other items of interest:
http://en.wikipedia.org/wiki/Category:Old_Ordnance_Survey_map_images