There was a campaign I heard about in Brighton which looked at this. It was run as a Labour party political organization and they performed regular inspections of letting agents in their area to see whether they complied with national legislation such as openly displaying a list of their fees including any VAT associated with them. I haven't heard of them for a while but they definitely were around. I think the NRA do have a list of letting agents and their fees, you'd have to ask them.
just a general question, does anyone know the name of that organization in Brighton of it they're still around?