Hi Joan
All supposition at the moment but there is a marriage of a Joseph Shimmin to a Jane Jones on Lancashire BMD 1878 West Derby Registry Office. There is also a death for a Jane Shimmin aged 30 on FreeBMD March Qtr 1889 West Derby 8b 467 - age fits and couldnt find any other Jane Shimmin born around same time on 1881 Census.
On IGI there is a baptism for a Joseph John Shimmin 1 May 1859 St Mathews Douglas Isle of Man ) .(Father Thomas Shimmin, Mother Jane - possible marriage of this couple 9 Januuary 1856 Braddan Thomas Shimmin and Jane Hudgen).
The birth on FreeBMD Dec Qtr 1885 was also for a Joseph John Shimmin - perhaps your Grandfather then?