Both work on Sky (first one with www. prepended - seems to be a config issue), but the second link looks like just a TPB mirror/proxy - it has the search for torrents mainly. That's something completely different than the first link, which is actually a promotion site.
promobay.org resolves to 108.59.2.74 for me, and www.promobay.org resolves to 108.59.2.75.
The first is blocked for me on Virgin, but the second works fine. This does look like a DNS issue on the part of TPB, rather than Virgin blocking promobay.
it might be surprising to find that Talktalk and bt (i think) went to court fighting the original blocking orders, they were very unwilling to implement mandatory blocking
