The height limit for model aeroplanes - be they quad/hex/octo copters, electric fixed wing, turbine powered model jets etc is 400ft as far as I am aware
The 400ft limit is only in controlled airspace and within 3nm of an airfield.
There was rumour of new legislation regarding remote aircraft/drones/quadcopters (specifically commercial ops <2kg) being released prior to the end of this year, I guess given the track record we might see it around 2025...