"Halal Nandos" is not certified halal by anyone.

Nandos claims that it is supplied halal poultry by a company called Cargill Freemans of Newent.

"Halal Nandos" branches hold certificates that say "Cargill Freemans of Newent supply halal poultry to this branch" or words to that affect (as mentioned on Nandos website).

Cargill Freemans of Newent are not certified halal suppliers by either of the two leading halal certification bodies in the UK; HFA or HMC.

The above point raises the question, who is certifying that Cargill Freemans of Newent supply halal poultry? Well, according to Nandos Halal page on their website, Cargill Freemans of Newent are "authorised by the Islamic Institute of Jurisprudence" who are apparently "one of the UK’s leading suppliers of Halal chicken", which is simply not true because...

 A simple Google search shows that "Islamic Institute of Jurisprudence" don't have a website.