when you say buzz do you mean hum? is it a 50 or 60 cycle hum? you dont want to eq it out or use a hum eliminator as well... your just destroying your tone by doing that. if it is a 50 or 60 cycle hum (chances are 50 because your in the uk) its cable inductance and a ground loop problem. have you tried using balanced cables in your fx loop and for your guitar cable?