DBS

I am writing to get the information about DBS check. I am British national of Indian origin. I was moved to UK. In my Indian passport I had only my forenames and no surname as I never had my surname in any of my official Indian documents. In India it is not compulsory to use ones surname for discriminatory reasons. In UK as a rule a person must have a surname.So when I was given British passport, my forenames were put in surname section. ( Quote from Her Majesty Passport Office- Where an applicant has just one name either on their birth certificate or by change of name deed, this should be shown in the surname field with three X’s shown in the forename field).

My question is that in what way shall I put the name on the DBS application form as surname mentioned in my British passport is not my surname but my forenames. Before getting British passport I used to write first part of my name as a forename and last part of my name in surname section and used to explain to the concerned person. When I applied for my DBS I put my name is this way and explained to the person and showed my passport to the concerned person. As I have not change my name but my official documents ( British passport and Indian passport) show my name in different way. Could you please provide any advice in this matter? I am about to apply for new DBS.