dear carole, i found betty and george raw on the 1841 online ancestry site, interestingly it was their granddaughter sarah raw b about 1823 that i was looking for, found her living with the grimshaws birth given as 1816?, and then noticed at the rhs bottom was george and betty.
have looked at the enumeration districts for lancashire for 1851 as was going to trawl through the pages but only gives prestwich cum oldham whose only entry is the oldham workhouse . have looked at middleton and crumpsall but prestwich itself was a reasonable size so can't work out why not listed.
the plot thickens, janet