refree justification

Hi,

I could not find a topic on this and hence asking this question.
I claim that one of my refrees is manager in my office and the other is my friend,
The manager of a vat registered company although eligible. But do I have to show any extra documents to substantiate the fact that I chose him/her for them being in that position ?
In the other words , do we need to submit proof for the eligibility of the refree to refer the person applying ? Eg:- the current business card of the manager or the current letter from solicitor telling that they are the solicitors etc.,

Does UKBA needs to be convinced that the refree is infact eligible to be a refree ?

Thanks.

No.

(But they might do their own checks to verify that).