It is one of the quirks of the system. The search of the site is updated in the early hours every night, so that area should appear if you search again tomorrow. The suggested areas are got using a different system (which isn't appropriate for the main search as it is based on lat/long rather than name) which is why they appear in real time. It is done this way to reduce the load on the system (and is a lot easier programatically).

I have to chuck in a couple of improvements to the search so that you could search for pubname Hampstead, those should go in around Mon/Tues.