Business rates reduction no win no fee

Hi people, as some of you are probably aware I help run a social club on a voluntary basis and as in any business we are always looking at reducing our overheads. We have been approached by an organisation that tries to reduce rates for businesses on a no reduction no fee basis. If they succeed we would have to pay them 45% of any savings. My question is has anyone used an organisation like this with any success or indeed tried themselves to get reductions in their business rates and been successful or not and how difficult did you find it?
I would appreciate any of your experience.