Although cartels are illegal and in no way am I suggesting that estate agents collude.... they will know each other's rates, the market, etc better than Joe Bloggs so would this approach work? It's all worth a punt though, eh, considering the wallah in danger.
The difference between 1% and 1.5% of a 200k house is a nice little earner, Rodders, and I would imagine EAs fight to keep their margin - what say you, Digsy my son?