Hi,
Regarding 73 Southfield Road and the tag addr:housename=73 Southfield Road, the name is not 73 Southfield Road nor is it 73, it has no name. The dwelling is an end terrace house not a semi-detached house. also the city is London not "London Borough of Ealing".

The above-mentioned points also pertain to numbers 71, 69, 67, 65, 63, 61, and 59.

Lastly the dwellings a terraced houses, they are joined by party walls. There are no gaps between them. 

I've made amendments so that the terrace is mapped to OSM practice. I hope you can see/understand what I've done. Need any help please just ask.

Regards Bernard. 