I’m not sure where the package six comes from! It could be a problem with pybluez.
You can just comment out the var-log.mount for the moment but be aware that will prevent Git updates.
A better way is to create a drop in.
sudo systemctl edit emonhub.service
put the following in
[Unit]
Requires=
After=network.target
save.
you then need to reload the daemon
sudo systemctl daemon-reload
Then restart.
(edited as I had missed out the [Unit])