"I am the one who had this issue. All my educational documents have first name and passport and work exp have first name plus surname.if you need a proper format..email me your id..otherwise any lawyer can create a document for you and take the print out on twenty rupees stamp paper and get it notarized."
Doesn't this mean that you actually do have a surname?
I faced almost same problem when filling up my application.My passport shows name as,
Given Name: Bijoy Purantharapully Job
I searched a lot and finally wrote the full name in in family name coloumn and left given name coloumn blank as help button near to each question in the application says (? button near to each question)
I got my grant and name listed as Bijoy Purantharapully Job.
I suggest to read carefully the help button and try to get possible help before filling up.