BenB

Thanks - I was nervous! It's the sort of thing I'll do on a Friday afternoon, then brick the whole site and panic about being offline for a weekend!
So I waited for the beginning of the week and moved  everything from my root folder into a backup file, then copied the entire wordpress site back to the root.
Tons stopped working! I was planning on running a migration plugin from within wordpress, but I couldn't log in without a cookies error, so I ended up asking my hosts for help. They reverted my very busy htaccess file for a default one and that brought things back to life. Then they thankfully ran the script to update all the links in the site to the new address, so I didn't have to do it myself.
So I guess if I hadn't have had a glitchy htaccess file I may have found it easy enough, but I'm so glad I had the hosts to help, and I'm glad I finally bit the bullet and simplified my site, it was pretty crazy having some pages on one system and some on another! I've now run dead link checkers, a 301 redirects plugin (so I never have to touch htacess again and risk killing the site! )

Yes, focus on the region. Make sure google knows where you are.
On the blog posts, bin the small images. Just show the images full size. Better for your visitors and it means you can get rid of another plugin.
As to the site location, build everything and then just move the Wordpress bit to the domain root. Your host should be able to do this for you in a nanosecond.

1. Has your Google my business listing been verified?
2. Are the address and other details on the Google business listing EXACTLY the same as those on the website?
3. Is the website linked to your Google business listing?
4. Google may well consider the main website and the blog to be two separate sites.
5. Google may not be indexing the blog because there is nothing to index. All the galleries are dynamic - which means all google may see is an empty page.
And it's not helped by a woeful page speed score. 24/100 on the blog and 33/100 on the main site. Google puts great store on page load speed. And there is almost zero useful indexable content.
If you want google to site up and take notice you need to make the blog the main site (with additional pages) and get words on the blog posts. Lots of words. and stop repeating the business name in the titles. Google really doesn't like this.
And this is the title on your homepage "Wedding Photography, Lavenham Photographic". Google is just going to lump you in with every other wedding photographer site in the UK.
That being said, a search for "wedding photography lavenham" has your detail in the side bar with your 17 google reviews. so it's not all bad.

Not alt text, it’s captions you need. Google wants to see the words on the page. Maybe not every image, but enough to describe a group of images.