Hello, I am just thinking of replacing the windows of the hatch doors with the conversion windows of the company Alpincamper. These are available in 2 versions: *Set 1: for installation in a specialist workshop (recommended by the manufacturer) *Set 2: for self-installation see https://www.alpincamper.de/current or short video at https://www.facebook.com/…/?… For my consideration, I have 2 questions: 1. What do you think the installation in a specialist workshop will cost? 2. Would you like this in a or would you let this be done in a “free” way?