It’s good to show loyalty to your favorite local dive shop. However, your needs are important too. Your LDS understands this. You (the customer) are the reason why they are in business.
Although I support my favorite LDS, and I am friends with the owners, there are times when they simply can not meet my needs at a particular time. In that case, I do use other facilities (though not often).
What I usually do is explain my needs to the folks at my LDS and ask what they can do to accommodate me. If they are not able to do what I need, then I ask for recommendations. In this way, you are letting them know that you considered their services "first". And maybe they will point you to another facility that can help you.
Just a suggestion.
Ron sends