Found this...
http://www.hmprisonservice.gov.uk/adviceandsup port/keepingintouch/locationservice/.
Not sure if this is what you found but he needs to consent to disclosure about his whereabouts.
Would he do this? If not have you tried googling his name or archives of local papers online?
It may come up with an article if there was a death involved.
If he is refusing to pay costs and your friend wants the court order enforcing then maybe the lawyer who acted could find out or maybe even the CAB if you asked them nicely, they may have more persuasive power.
Or is it just she wants to know he is safely behind bars and away from her?