PBS TIER 1 GENERAL DEPENDENT APPLICATION

HI,

I am applying for extension to leave to remain as PBS dependent (tier 1-general) while, my husband has got an ILR and is a british citizen through tier 1 route and i have problems in answering few questions.
Question in the application is as follows:

Q-what is the reference number of most recent application of the PBS main applicant that you are dependent on?
(which number should i fill ,my husbands TIER1 REFERENCE OR ILR reference number OR Naturalization or British citizen)

ALSO, I get child benefit because of my husband being a British citizen but the money comes in my personal account.
Should i enclose this information too in my application?or Not?

Many Thanks,
ref786