Arent shop assistants so helpful, Tintub! But now that your SO has seen the results of that gratuitous help, perhaps she can be persuaded otherwise.
As for the portafilter flaking....Ive had mine in daily use (at least 3 times daily) since February and not a hint of problems. Take it right back. Brass is a soft metal and will probably quickly infuse with staining coffee oils. Much easier to clean oil off chrome.