John Lewis Assessment Day

Tried posting this earlier but my internet buggered up. Cant find it now so hopefully this won be a double post.

Anyway Ive been invited to an assessment day with John Lewis next week and have been advised that the dress code is smart casual. Obviously I know jeans are a no go but I'd rather not go as far as a full suit. I was thinking something like this maybe??

http://imagecache.asos.com/inv/T/23/158/483686/Grey/image1xl.jpg

Has anybody been to one of these? How would you describe the attire and has anybody who went on the slightly less rigid side of interview wear gone on to get a job?