Is there any way of finding out someone's ex directory number?

 

Only the police are able to do that....... unless you have dodgy contacts at BT

 

There shouldn't be, that's the whole idea of XD. Although there used to be 2 types of XD, the "I just don't want my number in the book, but Directory Enquiries can give it out", and the full "Keep it secret" version. Whether this is still true, especially with all the directory providers and websites I doubt it.

Besides, you could be some psycho stalker type, so I'm not going to suggest Google.