I look out for that off flavour then, as I have a light pseudo lager in the brewbag fermenting at the mo. I used about 27% ASDA cornflakes. It'll be a shame if that's what happens as it's a stupidly cheap brew to make.
Hope yours turns out OK. They were using some odd cereals I think it was things like, coco-pops, luck charms, other weird American brands.