Hi themedicalengineer!
It does seem very odd that a company that manufactures insulin devices and BG monitoring equipment would take this stance. I suspect Lorna is right and they have some kind of H&S policy that states all medical-related activities should take place in the medical room. Do you have an HR department? Perhaps you could arrange to see an HR advisor and ask why they have introduced this rule. Explain your preference to test and inject at your desk and listen to their reasons. If they have good reasons, you would probably have to accept it and just make arrangements with them to ensure you always have access to the room for testing and injecting. You might find, though, that it is just an individual department manager's preference - in which case, HR would probably support you and help sort it out. Personally, I would welcome a medical room to use for my injections, but I would want my tester and supplies with me at all times in case I needed to test in a hurry if I felt I was getting a hypo. I would also probably not be happy storing my insulin pen in a medical room that other people have access to, so you might ask how your insulin would be kept secure. Perhaps you could try to reach a compromise whereby you inject in the medical room, but keep your tester and insulin with you at your desk?
I don't know if you have a case under the DDA because the company clearly is making reasonable adjustment by providing a medical room - as long as it's not too far away, your supplies are stored securely, they don't try to restrict your access to it or the number of times you can test and inject etc. I find with work-related problems that it is always best to try to sort it out amicably first. At the end of the day, you still have to work there and being in dispute with your managers is never pleasant. Also, if you do end up in dispute and want to make a case for discrimination, you will need to show that you have behaved reasonably as well. Keep notes of all dealings over the issue and make sure yoou get any reasons, agreements etc in writing.
Hope you get it sorted out quickly.
Smidge