There are 2 marriages recorded for Thomas Watson in 1909 one for Basford and one that is Nottingham but I'm unsure which one it would be
Queenie replied and confirmed which one to apply for so that's great.
Apologies if you already know this:
https://www.freebmd.org.uk You can add in a spouses name to help narrow down the search .
Search for Thomas Watson and add in "Harriet" as his spouse's first name, search a period of 1908-1910 (per that 1911 census, they'd been married 2 years but widen the search a bit to be sure) .
That search brings up just one result from the whole of England and Wales
Q2 1909 Watson Thomas Reg District: Basford vol 7b page 351
- sadly its rarely 'that' easy :-)
The result just lists one name - Thomas Watson so click on the page number (351) - there were usually at least 2 marriages on each page in the register- and it will show you who was on that page
and one of the brides was Harriet Emma Smith so that's the one you want.
According to the 1911 census transcript Queenie supplied, Harriet was born in Gotham.
In the results for that marriage on Free BMD, click on the District name of Basford - that takes you to a page that says it "spans Nottinghamshire and Derbyshire" and if you click on the word 'here' where it says you can get more info, that takes you to more detail about the places within that Registration District - and Basford includes Gotham so that's a little extra weight to add to be it being the right record, as that was her birthplace.
That looks like a lot written down, but it only takes a few seconds to actually do it.
Boo