They seem to be the exclusion to the rule.
Hence their PR talk of a special deal with BT Wholesale ages ago.
Either that or the other providers are bailing on the white label service, and Plusnet offering is meeting their needs better, or TalkTalk are.
To be honest if the Orange support is really people answering the phone who are run by BT Wholesale, the support knowledge is very bad, but then you don't get a lot for minimum wage these days.