Sorry to disagree stevecebu, an MP cannot do anything about a workaround to the immigration rules. Period.
Number 1 to follow is that each application MUST be fully compliant with the strictly defined requirements. The ECO's and caseworker have NO discretion at all.
BTW there is no discrimination against folk on benefits such as DLA. They qualify for exemption against the Financial Requirement
and only need to prove 'adequate maintenance'.
I do agree that under normal circumstances it's not necessary to use an agent.