It is always important to make sure that you receive a design visit from a bedroom designer beforehand. When they turn up they should be professionally dressed and be asking the right questions. During the design visit they should be measuring up the room in detail including the ceiling height. This visit should be free.
There are many companies on the market that claim to fit made to measure furniture, whereas their units are in fact fixed sizes. Make sure that the company has completely custom made bedroom units so that your bedroom space is totally utilised when the furniture is fitted. So the bedroom wardrobes, draw and cupboards should all be totally bespoke.