Sorry to hear about the ongoing issues Paul. Checking things over from here there's no obvious issues that would be causing this.
To try and help us narrow this down can you please upload your Hub/network connection details so we can check to see if there is a problem there? If you're unsure how:
In your browser’s URL box type in http://192.168.0.1 (or http://192.168.100.1 - if in modem mode) and hit return. Click on the “router status” icon at top right (SuperHub2) or the text at bottom-middle of first page up (Hub3) and then copy/paste 3 full sets of data onto here – from the downstream, upstream, & network logs pages. Please don’t include personal data or MAC addresses - if you copy/paste the data the forum software should blank them out for you.