I am currently working on a software project. While my company has many clients, this project focuses on the needs of a specific client, so we have been working directly with them. The software they need us to write requires other software that we do not have licenses for here, but they do, so any work done for testing and debugging needs to be done by me on their computer via a remote-access client. The problem arises with this. I can write the code for the program here, but because we don't have the needed licenses for the third-party software, I cannot do any actual testing here, so after I am ready to test my entire ability to work on it requires accessing their machine via remote-access. I will email them requesting them to help set this up since it requires both parties' input to do so, usually an hour or so before I need it to give them time. Often times, though, they will either completely ignore my emails, or respond with something along the lines of "I'm ready, we can set it up now", but when I go to do it they take a long time (often > 30 minutes) to actually do it after they send that message.
So, my question is, how can I address this as a problem tactfully? They are a client after all so I don't want to upset them, but their rudeness and seeming lack of respect for my time is not only annoying, but directly interferes with my ability to do my job. Sometimes I'll send follow-up emails checking to make sure they are receiving them or are ready, but I don't want to do this too much for fear of being annoying. What can I do? Thanks for any help!
EDIT: Just for clarification because I think my wording may have been a bit confusing, the client only needs to set this up once/day, not every time I need to test something. This is a machine at their site that is generally unused during the day, so they essentially just click an "OK" button once at the beginning of the day allowing me to access it, then I stay connected to it the entire day.