Path with "/" against Path without "/"

When I was messing with it getting it to work.. I had to put the folder name that boost generated in the htaccess. My domain is www.bexleymarine dot com. When I enabled boost, it created a folder cache/bexleymarine.com/----all the files are here including subfolders each subfolder named with the path and the files in each path.. in may case... cache/bexleymarine.com/ service/ new-outboards/ and so on/

RewriteCond %{DOCUMENT_ROOT}/cache/bexleymarine.com/index.html -f

I just looked on the server for the file name in the cache folder and put that name in the htaccess in place of host_name or server_name. I know that is not right, but it is working. This is a one Domain or one site installation in my case.

I see you may be trying to access the path differently that boost is made to do.. your file may be visible with example.com/cache/your-domain.com/folder-name/file-name.html
on my setup
www bexleymarine.com/cache/bexleymarine.com/service/service-department.html
or let htaccess do the path to cache
www bexleymarine.com/service/service-department

EDITING
I just went on your site and checked out the urls for the cache part and it is right. I don't think drupal uses any trailing slash for a path. You would have to add a file or page name.

The Global Redirect module can be setup to not allow any url's with a trailing slash. On the Global Redirect configuration page set Deslash: On. Then clear your boost cache, you shouldn't have any more issues.