The reaction you will get will depend on a variety of things:

Your reason
How you broach it
The individual receiving this information

Then there is the reaction from the consultant. Most Consultants will be patient and listen to you. Perhaps a little patronizing but shouldn't give you any grief.

Honestly, you might get some hostility but if you go in being diplomatic it should be ok. It will depend on the consultants availability as well. If it's a clinic, they might not be avail. But do expect the "this is a public hospital, you can't pick and chose" speech.

I have requested a consultant before. Actually, I presented to ED via ambulance and asked them to call my consultant who I had seen the day prior. The intern took offense and barely gave me any treatment at all. It took the nurse to see me have another attack (pain) who got the on duty consultant who listened to me and then called my consultant on the mobile immediately.

My advice would be to go in and patiently and calmly explain your reasons for wanting the consultant - take the emotion out of it. Don't make threats (I hear people say "I'll report you!" all the time and it gets them nowhere) but if you are refused a consultant, ask what the process is at THAT venue for escalating the problem as you feel DS requires more experienced care givers. Feel free to contact the patient liaison person to assist you with that too.

Good Luck.