Wow that is confusing.
Firstly I'd be tempted to think that one of the certs is incorrect, despite the fact that they seem to match up.
Do you have any other census info at all, or any other certs for the family that might help prove addresses?
So just for me to get this straight:
1865
Thomas Harris - labourer - parents Robert Harris and Elizabeth Sinclair
married
Margaret Black
1886
Thomas Harris died. Wife Margaret Black.
Parents Samuel Harris and Sarah Haggin
Informant brother George Harris.
I can't make out the addresses and as I'm at work can't spend much time playing around!
