Thanks Merlin, I could provide a wireshark log of what's happening when the issue appears if you are interested?!
Thanks, but that wouldn't really help. I do know that networkmap does various connection attempts to determine if a certain device is a printer, however I don't know if just one specific test there is responsible for the wake up. I tried simplifying the test by only connecting to the usual LPR port instead of also submitting a test job, but reports indicated that it wasn't enough.