I should try the st Caths Index first!
There is a 1851 census index -its quite a few volumes -Manchester was big
even in those days! published by Manchester FHS.
The Cathedral or collegiate church, aka St Mary, St Denys & St George used
to be a place at one time where anyone married with few questions asked ( i
suppose pre 1800) but I should imagine it was much the same later. The
early ones are published by the LPRS but thats pre1700. The mormons will
probably have the BT's on film.
As I said try St caths 1st -it'll make life easier.
Lancastrian exiled to darkest Yorkshire!