I'm fairly sure I've seen polenta even at Tesco's. Seems to me it was with the rice, lentils, couscous, etc.
Regarding the chocolate chips, I never used them even in the US. Too small and blah. I always bought baking chocolate (dark and white) and cut it up into big rough chunks. Yummm! There's nothing like homemade white chocolate & macadamia cookies!