On viewing the actual census there is something after Northumberland which they have transcribed as Soke. Now we have established it is not Soke, any suggestions as to how I can take my query forward?
Firstly treat 'any' transcription as a 'pointer' to an original record and whenever possible check the original record to see if it has been transcribed correctly. If you find errors, report them to the database owner - hopefully they will be reviewed and corrected which will help others in the future.
Widen your searches to Northumberland and Durham when looking for Joseph's birth. People moved around a lot between the two counties (and even further afield).
I just did a quick look in Family Search for a Joseph Robson born in Northumberland between 1820 and 1832, with a father called John and there were quite a few baptisms which matched that and also gave mother's first names..
If it were me, I'd work my way through those, check burials to see if any died and can therefore be discounted, check 1841 and 1851 census returns to see if they can be found and discounted and then see if there are any left that could still be viewed as 'possible'.
Sometimes its a long hard slog :-(
Boo