We had the same from some companies and had no problem with a competent rep who actually called to veiw the house before quoting. Our windows are huge. You just need to break them into sections, we have a large square bay and in this case both side windows open but not the front window. All windows are divided into 3 sections for uniformity and it looks well imo.
Tilt and turn are a nightmare if you want blinds, our neighbour ended up with 56 roller blinds in their house as each section of window needed it's own blind!!
PM me if you want the reps name that we used. We are in Cork and went with a well established company. Like all companies it's often down to the individual rep on how practical and accomodating they are even in the current climate.