I have been having similar problems with two adult sites on .tv domains. The sites load but starting streaming causes buffering with initially 500 kb to 3 Mb download, this then drops down to 0 kb and will not show streams.
Using my alternative of a MiFi mobile unit on EE the sites load and run with no problems.
Both using Chrome browser or Safari; home link has around 70 Mbps on tests and MiFi only 15 Mbps so not my end.
Adult sites on .com domains do not seem to be affected.
check MYBT that web protect is turned off