Nildram at some point finished up managed or owned by TalkTalk (or may have been TalkTalk's business unit).
Just go on the TT forums and ask, the OCE's on there are very helpful and have helped other ex-Nildram users in the past.
I've just left Talk Talk Business and had 2 (still functioning!) @gotadsl.co.uk addresses, so TTB does indeed own that domain. Their helpline is 0800 083 3003. I suggest you ring them during weekday working hours, when you are more likely to get a UK-based responder.
Btw, I only left because they don't do FTTP, which has become available at my address, and the ADSL is inadequate for my household's needs.