Speed Dropped

I have had a 1 Gb connection for a few years now and to be honest, it's been great. Every now and again I have to reboot but it all comes back on fine and the speed has always been as advertised with a  reported 1100 mbps.

However in recent weeks I cannot get beyond 300 mbps which is what I was getting years ago before I upgraded. I am using a Hub 4 which is a few years old. 

I was hoping it would resolve itself or a temporary glitch, but this appears to be my new speed. 

Any suggestions.