I have now collected 6 Nandos stamps so far on two different cards (4 on the first card and 2 on the second).
On their website, Nandos have said that you can't transfer stamps from one card onto another. However it was a staff member who gave me the second card because I had wanted to save up to 6 stamps for a 1/2 chicken rather than use 3 stamps for a 1/4 chicken. It's quite confusing the way the have devised this scheme. Anyone know more about this?