External Benq GL2460 Display Issues

Hello,

I have the Benq connected via Thunderbolt - HDMI, and here are some very irritating issues I experience:

Audio: When waking the computer up from sleep, it turns the default audio device output to the BenQ monitor. Which i only have muted from the display anyway.

Sleep: When i put my imac to sleep, the BenQ monitor starts to flash blue saying "no input detected" is there anyway to stop it doing this?