Best suggestion.My suggestion would be to look for a great Integrated Amp within your budget, rather than "Receivers" of any kind. There is just no comparison...Spend upto half, maybe even match the amount you spent on the KEF.
You have a resolving set of speakers costing around 2K$. Look for a refined amplifier around the same price ballpark to get the best out of your speakers. Don't settle for anything less.
You could go to the KEF dealer and demo with the best amplifier they have to get an idea what these babies can do.