I do realise you had the marriage certificate. I posted it for others who may want to help you. You did not give complete information in your opening post.
Some records for your further exploration.
1891 census Liverpool. St Thomas
William McClelland   57   Sea Mariner    married (visitor in house of Edward Whiting)
Mary McClelland   52   married   born Liverpool
1911 census Toxeth Park Workhouse?
William McClelland 77, married, former seaman merchant service, inmate in workhouse?