Angie, I've tried every combination on 1881 census, reversing the name, wildcard, just William Bowyer and still nothing!
You haven't mentioned having his d cert, if that says more than just the town he died in there may be enough to try an address search for 1881. They do seem to have flitted about somewhat, very inconsiderate. He died in Greenwich so had he returned to his own area, or just visiting?
What about Sarah's d cert ?
Mazeppa