I took your advice and setup a HAProxy/heartbeat pair.
It took some considerable reading to pull it off as it's not really made for that and most people use it for web proxying.
That being said, I thought I'd paste the revelent part of the config here to save others some time if they attempt it
This may not be the best way, but it is working.
listen db_proxy 192.168.1.190:3306
stats auth someuser:somepassword
# cookie JSESSIONID prefix
# option httpclose
# option forwardfor
# option httpchk HEAD /check.txt HTTP/1.0
server c1 192.168.1.191
server c2 192.168.1.192
I can't seem to get the stats to work though. I'm not sure what I have messed up. I thought stats enabled and the password was all that was needed, but apparently I'm missing something.
Hopefully that helps someone!
Thanks for your help Falko!