Your problem is not due to lack of brand awareness in northern part of India as such. Just because of unwillingness of the few job candidates in sequence, you cannot correlate their non-acceptance of the job with the brand image of the company. There are several cases wherein Head Offices are located in Mumbai, Bangalore, Chennai, Hyderabad etc and they have staff at Delhi, Patna, Kolkata etc. Many times they work from home.
I feel that the problem could be due to wrong Job Description (JD) posted at job portal or the newspaper ad. I recommend you mentioning clearly that the person employed will work at client's location. However, his reporting authority will be at HO of your company. Tell the candidate that your client will make arrangement for his office.
How about interviewer? Has he been trained sufficiently on the interview handling skills? Instead of projecting image of the company, is interviewer, projecting his image of being south Indian and thereby creating hesitation in the mind of the interviewee?
25th November 2016 From India, Bangalore