Never heard of them either but there would be 100's I've never heard of.
The "unbiased" comment is technically not correct as they would be "biased" towards lenders in the panel (45). Although lenders pay difering commisison levels, I don't see the issue of commission being an issue as a broker should be placing the business where it fits best with your current & future needs/goals. If the Mb isn't doing this the business is most likely to walk out the door in the future.
Unless your accountant is a mug, I would suggest he/she wouldn't have such a referal programme in place unless they were happy with the service the MB was providing unless of course it's a new arrangement or very few clients have taken up the offer. In this case they too are flying blind. Kudos must be given to your accountant for disclosing the commission arrangements.
I actually have a couple of such arrangements in place with solicitors that were set up when I first started out. These solicitors still refer deals to me know.
Have a chat to them and ask a few questions so you get a feel for them. If you're not comfortable look elsewhere.
OH and just on the 45 lenders available. It always makes me laugh a little and people using those kinds of figures for bragging rights. The chances are that some of these will specialise in non-conforming loans, some commercial and others that they have never used for competitive reasons. My bet it that they would be lucky to use 10 of them on a regular basis.
Regards
Steve