Wherever people marry, they sign the register or leave a mark 'X'.
The General Register Office Indexes are just that, an index. They point the way for you to order the cert either from a local register office or the GRO at Southport.
If they married in a register office, you won't get to see the signatures, only a transcription made by the registrar on the copy that is supplied.
If they married in church, again you get a transcription but you may get to see the actual signatures if the registers have been deposited in a local archives for safekeeping.
The London & Middlesex Anglican parish registers deposited at the London Metropolitan Archives have been digitised and transcribed onto the Ancestry web-site.
There isn't a match for Annie Teresa Dowling & Edward Harry Houchin at Marylebone. Which means they married in a register office, or they married in a Catholic church, Quaker meeting house or synagogue or the registers haven't been deposited for safekeeping.
The only way to know for sure where they married is to purchase the cert from the GRO at Southport (
www.gro.gov.uk) and then follow up from there.
If you can get access to the 1911 census, you can search on the adress to see who was there for 1911, but that might be too early for you.
In 1916 women weren't eligible to vote and the registers weren't published because of the war, so there won't be an entry for her on the electoral registers.
Kelly's or other street directories don't give detailed lists of who was residing at a premises, generally only the 'head' of the household.
Sorry I can't help you take your request any further forward at this time.
Dawn