Cheers for your time on the phone today @KevinJones, and thanks for the summary.
I'm glad to see that armed with the logs we've given that you've been able to resolve the issue now.
I am genuinely sorry again for the bad experience you've been through for almost 2 months.
I have typed up feedback and e-mailed it to my manager for the NetOps team, as I appreciate we could've removed the global IP block a lot sooner and provide the logs without further info, based on the telnet session you'd done.
This has actually been a learning experience for me as well, so thanks again for taking the time to speak with me.
In recognition of the inconvenience we've caused, I've added more detail onto the (now closed) ticket here > https://www.plus.net/wizard/?p=view_question&id=221847573 about a gesture of goodwill we've agreed on.
If you have further issues or there's anything else you need help with, feel free to get back to me and I'll be happy to help. 
Anoush Mortazavi
Operations Assurance Professional
Plusnet