No, it usually takes only a day to install your conservatory roof insulation.
You will undoubtedly get less direct sunlight when the sun is directly above. However, your conservatory should retain sufficient light through the side windows which will be comparable to a standard solid roof extension. The key benefit is that you will get far less glare from the overhead sun, keeping it cooler in the Summer and be able to enjoy the conservatory more than you ever did before.