It is the same strange urge which comes upon me in Sainsbury's when someone is desperately looking for mango chutney and I want to rush and find it and then go back and tell them!
It is always mango chutney that you can't find isn't it?! It's hilarious. In fact, the whole pickled items section is a complete mystery to me. Insane!
Always above the frozen food for some reason. i would put it near the jams personally, just past marmite but before you get to the dried herbs. I always have trouble with pizza base mix - obvious place would be near the pasta but its in the flour section. Madness!
There is certain psychology going on. They put seemingly similiar things far apart so you have to look for it and make impulse purchases on your hunt.
I'm always annoyed they put the chilled veggie stuff in the meat department.