Have you re-watched module 4 under consultation? I don't know if I've seen a formal questionnaire but I think Sarah did a talk on it once and may have referenced it. Mostly be yourself and ask them to show you the area of concern. Ask them what they would like it to look like if they could have it any way they wanted. Ask how they use the room and who uses it. Ask if they'll be working with you, you can explain what you'll be doing a little if you want. Sorting, organizing the keep pile etc. Mostly I listen and assure them its not the worst I've seen and not to be embarrassed if they mention it (which they usually do!) Congrats on your first consultation. Let me know how it goes.