Sounds like EE are classifying this as a gaming site. I know the old site (and places like RPG.net and UKRoleplayers) were/are frequently blocked by Websense because (a) they are a games site and (b) because they are a forum.
Definitely sounds like an EE problem. I notice that their help page about content locking contains this gem of advice
"We’re now blocking secure sites for Strict users (sites showing HTTPS in the URL). This means that some webpages you may have been previously able to access will now show as ‘Timed out’ or ‘No response’."
Leaving aside the sense of blocking secure sites at a time when everyone is being encouraged to make their site secure no matter what, I would suggest that you double-check your content lock settings and make sure they haven't been reset. If you've already done that, I'd suggest talking to EE. Their help page (which ironically is https and therefore may be blocked!) says that turning content block off should give you unrestricted internet access with no filter, so you should definitely be able to get here if you've got it set to off.
It's also possible that there is some kind of technical fault which is causing this, which is another reason to talk to them.