SL's are not secured as you say. Nor are court fines or CSA payments but you can't write them off either. If you think about it many many people would declare BR just on the basis of owing large amounts on any of these 3 types of "debt". Which is why they are exempt.
A matter of responsibility if you will, which isn't, as with loans etc, a business arrangement or a subsequent cost related to a business arrangement.
technically no, and it was me that advised you to put it there. The reason being it will support the fact, by way of additional detail, that you will be claiming a monthly allowance in order to make the loan repayments.
So it's there for information for the OR, but technically not a secured loan.