Hi Peter,
You'll want to make sure that your branch/location pages have a combination of the following:
- Links to the pages of the services they provide - if all branches deliver all products/services, then your main navigation should be fine, but if there are differences or specialties, you should highlight those on the location page (or a sub-page of the location page).
- Unique content - at the very least, an embedded map and a picture of the branch.
- Any additional relevant content that is unique to that location.
Then, on your Category pages, you'll want to make sure you have clear info about your locations. If you only have a handful of locations, you can probably include the full citation (name/address/phone) info for all of them in a footer or sidebar. If you have many locations, you'll want to make sure the location finder is a key part of all the category pages.
There are also off-site things you can do. If your reviews, social media mentions, and backlinks mention specific services while linking to a specific location, that will help that branch rank for those categories.
Hope this helps,
Ira