[tors]

I am in the throes of starting a letting agent based in Essex UK. The price range of properties I will target are from 250k to 2 million. I have been able to assertain that local agents will charge between 10-12.5% (full management) on the lower end properties but I am struggling to find out what they charge on the higher end. Does anyone have experience in how to find out what they charge or willing to share with me what they charge (if in the same business).
Is there a formula for working out what each property should pay you depending on the size (residential not commercial).